diff --git a/NEWS b/NEWS
index 495e4af7..e8272bb0 100644
--- a/NEWS
+++ b/NEWS
@@ -1,2216 +1,2219 @@
 Noteworthy changes in version 1.15.2 (unreleased)
 -------------------------------------------------
 
 
  * Interface changes relative to the 1.15.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ gpgme_key_sig_t                       EXTENDED: New field 'trust_depth'.
+ gpgme_key_sig_t                       EXTENDED: New field 'trust_value'.
+ gpgme_key_sig_t                       EXTENDED: New field 'trust_scope'.
  GPGME_KEYSIGN_FORCE                   NEW.
  qt: CryptoConfig::entry               CHANGED: Added overload; deprecated old
 
 
 Noteworthy changes in version 1.15.1 (2021-01-08)
 -------------------------------------------------
 
  * Fix another bug in the secret key export.  [#5046]
 
  * Make listing of signatures work if only secret keys are listed.  [#3580]
 
  * Fix build problem on FreeBSD.  [a6220adf30]
 
  * qt: Avoid empty "rem@gnupg.org" signature notations.  [#5142]
 
  * python: Fix key_export functions.  [#5149]
 
 
  [c=C35/A24/R1 cpp=C18/A12/R1 qt=C12/A5/R1]
 
  Release-info: https://dev.gnupg.org/T5225
 
 
 Noteworthy changes in version 1.15.0 (2020-11-12)
 -------------------------------------------------
 
  * New function gpgme_op_setexpire to make changing the expiration
    easier (requires GnuPG 2.1.22). [#4999]
 
  * New function gpgme_op_revsig to revoke key signatures (requires
    GnuPG 2.2.24). [#5094]
 
  * Support exporting secret keys. [#5046]
 
  * cpp: Support for set expire operations in the C++ bindings. [#5003]
 
  * cpp: Support for revoking key signatures in the C++ bindings. [#5094]
 
  * qt: Extended ChangeExpiryJob to support changing the expiry of
    subkeys. [#4717]
 
  * qt: Extended QuickJob to support revoking of key signatures. [#5094]
 
  * qt: Added QDebug stream operator for GpgME::Error.
 
  * Require a somewhat newer version of libgpg-error (1.36).
 
  * Interface changes relative to the 1.14.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_op_setexpire_start                   NEW.
  gpgme_op_setexpire                         NEW.
  gpgme_op_revsig_start                      NEW.
  gpgme_op_revsig                            NEW.
  GPGME_REVSIG_LFSEP                         NEW.
  cpp: Context::setExpire                    NEW.
  cpp: Context::startSetExpire               NEW.
  cpp: EngineInfo::Version::operator<=       NEW.
  cpp: EngineInfo::Version::operator>=       NEW.
  cpp: EngineInfo::Version::operator!=       NEW.
  cpp: StatusConsumer                        NEW.
  cpp: StatusConsumerAssuanTransaction       NEW.
  cpp: Context::cancelPendingOperationImmediately NEW.
  cpp: Context::revokeSignature              NEW.
  cpp: Context::startRevokeSignature         NEW.
  cpp: UserID::Signature::operator<          NEW.
  qt: operator<<(QDebug debug, const GpgME::Error &err) NEW.
  qt: QuickJob::startRevokeSignature         NEW.
  qt: QuickJob::result                   CHANGED: Made params 'auditLogAsHtml'
                                                 and 'auditLogError' optional.
 
  [c=C35/A24/R0 cpp=C18/A12/R0 qt=C12/A5/R0]
 
  Release-info: https://dev.gnupg.org/T5131
 
 
 Noteworthy changes in version 1.14.0 (2020-07-16)
 -------------------------------------------------
 
  * New keylist mode to force the engine to return the keygrip. [#4820]
 
  * New export mode to export as OpenSSH public key.  [#4310]
 
  * New context flag "extended-edit" to enable expert key edit. [#4734]
 
  * Deprecate the anyway non working trustlist functions.  [#4834]
 
  * cpp: Add convenience API to obtain remarks. [#4734]
 
  * cpp: The sign key edit-interactor now supports multiple signatures
    from the same key. [#4734]
 
  * qt: Extended signkeyjob to handle remarks and multiple signatures.
    [#4734]
 
  * qt: Added job API for gpg-card.
 
  * qt: The logging category has been changed to gpg.qgpgme to be more
        consistent with other qt logging categories.
 
  * Interface changes relative to the 1.13.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_KEYLIST_MODE_WITH_KEYGRIP              NEW.
  GPGME_EXPORT_MODE_SSH                        NEW.
  gpgme_user_id_t                         EXTENDED: New field 'uidhash'.
  cpp: UserID::remark                          NEW.
  cpp: UserID::remarks                         NEW.
  cpp: GpgSignKeyEditInteractor::setDupeOk     NEW.
  cpp: Context::exportPublicKeys          EXTENDED: New param 'flags'.
  cpp: Context::startPublicKeyExport      EXTENDED: New param 'flags'.
  cpp: Context::ExportMode                     NEW.
  qt: SignKeyJob::setDupeOk                    NEW.
  qt: SignKeyJob::setRemark                    NEW.
  qt: GpgCardJob                               NEW.
  qt: ExportJob::setExportFlags                NEW.
 
  [c=C34/A23/R0 cpp=C17/A11/R0 qt=C11/A4/R0]
 
  Release-info: https://dev.gnupg.org/T4996
 
 
 Noteworthy changes in version 1.13.1 (2019-06-13)
 -------------------------------------------------
 
  * cpp: gpgme_set_global_flag is now wrapped.  [#4471]
 
  * w32: Improved handling of unicode install paths.  [#4453]
 
  * w32: The gpgme_io_spawn error message is now only shown once. [#4453]
 
  * Fixed a crash introduced in 1.13.0 when working with S/MIME. [#4556]
 
  * w32: Fixed format string errors introduced in 1.13.0 that could
    cause crashes.  [#4440]
 
  * w32: Fixed an error in the new diagnostic gpgsm support introduced
    in 1.13.0 that caused crashes in low fd scenarios.  [#4439]
 
  * python: Fixed a DecryptionError Exception.  [#4478]
 
  * python: No longer raises BadSignatures from decrypt(verify=True).
    [#4276]
 
  * Interface changes relative to the 1.13.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cpp: setGlobalFlag                         NEW.
 
  [c=C33/A22/R1 cpp=C16/A10/R0 qt=C10/A3/R4]
 
  Release-info: https://dev.gnupg.org/T4551
 
 
 Noteworthy changes in version 1.13.0 (2019-03-26)
 -------------------------------------------------
 
  * Support GPGME_AUDITLOG_DIAG for gpgsm.  [#4426]
 
  * New context flag "trust-model".
 
  * Removed support for WindowsCE and Windows ME.
 
  * Aligned the gpgrt-config code with our other libaries.
 
  * Auto-check for all installed Python versions.  [#3354]
 
  * Fixed generating card key in the C++ bindings.  [#4428]
 
  * Fixed a segv due to bad parameters in genkey.  [#4192]
 
  * Fixed crash if the plaintext is ignored in a CMS verify.
 
  * Fixed memleak on Windows.  [T4238]
 
  * Tweaked the Windows I/O code.
 
  * Fixed random crashes on Windows due to closing an arbitrary
    handle.  [#4237]
 
  * Fixed a segv on Windows.  [#4369]
 
  * Fixed test suite problems related to dtags.  [#4298]
 
  * Fixed bunch of python bugs.  [#4242,commit 9de1c96ac3cf]
 
  * Several fixes to the Common Lisp bindings.
 
  * Fixed minor bugs in gpgme-json.  [#4331,#4341,#4342,#4343
 
  * Require trace level 8 to dump all I/O data.
 
  * The compiler must now support variadic macros.
 
  * Interface changes relative to the 1.12.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_set_ctx_flag               EXTENDED: New flag 'trust-model'.
  cpp: Context::create                       NEW.
  cpp: Key::isBad                            NEW.
  cpp: Subkey::isBad                         NEW.
  cpp: UserID::isBad                         NEW.
  cpp: UserID::Signature::isBad              NEW.
  cpp: GenCardKeyInteractor::setAlgo         NEW.
 
  [c=C33/A22/R0 cpp=C15/A9/R0 qt=C10/A3/R3]
 
  Release-info: https://dev.gnupg.org/T4376
 
 
 Noteworthy changes in version 1.12.0 (2018-10-08)
 -------------------------------------------------
 
  * Enhanced the JSON based interface tool gpgme-json to support Native
    Messaging as well as new Javascript code to support the browser
    site.  See lang/js/README for details.
 
  * Major overhaul of the Python language bindings documentation.
 
  * Even for old versions of gpg a missing MDC will now lead to a
    decryption failure.
 
  * Added context flag "auto-key-locate" to control the
    behavior of GPGME_KEYLIST_MODE_LOCATE.
 
  * New data function to create a data object from an estream.
 
  * Add more interfaces to the C++ bindings.
 
  * Improved error codes on decryption failure.
 
  * Lots of minor fixes.
 
  * Interface changes relative to the 1.11.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_data_new_from_estream                NEW.
  gpgme_decrypt_result_t           EXTENDED: New field legacy_cipher_nomdc.
  gpgme_set_ctx_flag               EXTENDED: New flag 'ignore-mdc-error'.
  GPGME_AUDITLOG_DEFAULT                     NEW.
  GPGME_AUDITLOG_DIAG                        NEW.
  gpgme_set_ctx_flag               EXTENDED: New flag 'auto-key-locate'.
  cpp: DecryptionResult::sessionKey          NEW.
  cpp: DecryptionResult::symkeyAlgo          NEW.
  cpp: DecryptionResult::isLegacyCipherNoMDC New.
  cpp: Data::rewind                          NEW.
  cpp: Context::setFlag                      NEW.
  cpp: Context::getFlag                      NEW.
  cpp: Context::createKeyEx                  NEW.
 
  [c=C32/A21/R0 cpp=C14/A8/R0 qt=C10/A3/R2]
 
  Release-info: https://dev.gnupg.org/T4109
 
 
 Noteworthy changes in version 1.11.1 (2018-04-20)
 -------------------------------------------------
 
  * Fixed build problems in the 1.11.0 release.
 
  * Added C++ interfaces which were planned for 1.11.0.
 
  * Interface changes relative to the 1.10.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  cpp: Key::origin                     NEW.
  cpp: Key::lastUpdate                 NEW.
  cpp: UserID::origin                  NEW.
  cpp: UserID::lastUpdate              NEW.
 
  [c=C31/A20/R1 cpp=C13/A7/R0 qt=C10/A3/R2]
 
 
 Noteworthy changes in version 1.11.0 (2018-04-18)
 -------------------------------------------------
 
  * New encryption API to support direct key specification including
    hidden recipients option and taking keys from a file.  This also
    allows to enforce the use of a subkey.
 
  * New encryption flag for the new API to enforce the use of plain
    mail addresses (addr-spec).
 
  * The import API can now tell whether v3 keys are skipped.  These old
    and basically broken keys are not anymore supported by GnuPG 2.1.
 
  * The decrypt and verify API will now return the MIME flag as
    specified by RFC-4880bis.
 
  * The offline mode now has an effect on gpg by disabling all network
    access.  [#3831]
 
  * A failed OpenPGP verification how returns the fingerprint of the
    intended key if a recent gpg version was used for signature
    creation.
 
  * New tool gpgme-json as native messaging server for web browsers.
    As of now public key encryption and decryption is supported.
    Requires Libgpg-error 1.29.
 
  * New context flag "request-origin" which has an effect when used
    with GnuPG 2.2.6 or later.
 
  * New context flag "no-symkey-cache" which has an effect when used
    with GnuPG 2.2.7 or later.
 
  * New convenience constant GPGME_KEYLIST_MODE_LOCATE.
 
  * Improved the Python documentation.
 
  * Fixed a potential regression with GnuPG 2.2.6 or later.
 
  * Fixed a crash in the Python bindings on 32 bit platforms.  [#3892]
 
  * Various minor fixes.
 
  * Interface changes relative to the 1.10.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_op_encrypt_ext             NEW.
  gpgme_op_encrypt_ext_start       NEW.
  gpgme_op_encrypt_sign_ext        NEW.
  gpgme_op_encrypt_sign_ext_start  NEW.
  GPGME_ENCRYPT_WANT_ADDRESS       NEW.
  GPGME_KEYLIST_MODE_LOCATE        NEW.
  gpgme_import_result_t            EXTENDED: New field 'skipped_v3_keys'.
  gpgme_decrypt_result_t           EXTENDED: New field 'symkey_algo'.
  gpgme_decrypt_result_t           EXTENDED: New field 'is_mime'.
  gpgme_verify_result_t            EXTENDED: New field 'is_mime'.
  cpp: Key::locate                 NEW.
  cpp: Data::toString              NEW.
  cpp: ImportResult::numV3KeysSkipped  NEW.
 
  [c=C31/A20/R0 cpp=C12/A6/R0 qt=C10/A3/R1]
 
 
 Noteworthy changes in version 1.10.0 (2017-12-12)
 -------------------------------------------------
 
  * Now returns more specific error codes for decryption to distinguish
    between bad passphrase, user canceled, and no secret key.
 
  * Now returns key origin information if available.
 
  * Added context flag "auto-key-retrieve" to selectively enable the
    corresponding gpg option.
 
  * Added flag is_de_vs to decryption and verify results.
 
  * py: Use SEEK_SET as default for data.seek.
 
  * cpp: Various new APIs.
 
  * Reduced spawn overhead on Linux again.  Added new configure option
    --disable-linux-getdents to disable this feature for very old
    Linux versions.
 
  * Improved the Python bindings build system.
 
  * Made the test suite less fragile.
 
  * Interface changes relative to the 1.9.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_decrypt_result_t      EXTENDED: New field 'is_de_vs'.
  gpgme_signature_t           EXTENDED: New field 'is_de_vs'.
  gpgme_keyorg_t              NEW.
  gpgme_op_delete_ext         NEW.
  gpgme_op_delete_ext_start   NEW.
  GPGME_DELETE_ALLOW_SECRET   NEW.
  GPGME_DELETE_FORCE          NEW.
  gpgme_op_conf_dir           NEW.
  gpgme_set_ctx_flag          EXTENDED: New flag 'auto-key-retrieve'.
  cpp: DecryptionResult::isDeVs         NEW.
  cpp: Signature::isDeVs                NEW.
  cpp: EngineInfo::Version::operator>   NEW.
  cpp: Context::createKey               NEW.
  cpp: Context::startCreateKey          NEW.
  cpp: Context::createSubkey            NEW.
  cpp: Context::startCreateSubkey       NEW.
  qt: QuickJob                          NEW.
  py: DecryptResult           EXTENDED: New boolean field 'is_de_vs'.
  py: Signature               EXTENDED: New boolean field 'is_de_vs'.
  py: GpgError                EXTENDED: Partial results in 'results'.
 
  [c=C30/A19/R0 cpp=C11/A5/R0 qt=C10/A3/R0]
 
 
 Noteworthy changes in version 1.9.0 (2017-03-28)
 ------------------------------------------------
 
  * Clarified meaning of the 'expire' parameter of gpgme_op_createkey
    and gpgme_op_createsubkey.  New flag to force a key without an
    expiration date.
 
  * New function gpgme_op_keylist_from_data_start to list keys from
    data objects without importing them.
 
  * New function gpgme_op_set_uid_flag to flag a key as primary.
 
  * New function gpgme_op_decrypt_ext to run decryption with special
    flags.  This can for example be used to unwrap keys (remove only
    the encryption layer).
 
  * New encryption flags to wrap a key (adding an encryption layer to
    an OpenPGP message) or to create anonymously encrypted messages.
 
  * Support for adduid and revuid operations in the C++ bindings.
 
  * Support for smartcard key generation in the C++ bindings.
 
  * Several new functions for the Python binding.
 
  * Many smaller bug fixes.
 
  * Interface changes relative to the 1.8.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_op_createkey          CHANGED: Meaning of 'expire' parameter.
  gpgme_op_createsubkey       CHANGED: Meaning of 'expire' parameter.
  GPGME_CREATE_NOEXPIRE       NEW.
  gpgme_key_t                 EXTENDED: New field 'origin'.
  gpgme_key_t                 EXTENDED: New field 'last_update'.
  gpgme_subkey_t              EXTENDED: New field 'is_de_vs'.
  gpgme_user_id_t             EXTENDED: New field 'origin'.
  gpgme_user_id_t             EXTENDED: New field 'last_update'.
  gpgme_op_keylist_from_data_start NEW.
  gpgme_op_set_uid_flag_start      NEW.
  gpgme_op_set_uid_flag            NEW.
  gpgme_op_decrypt_ext_start       NEW.
  gpgme_op_decrypt_ext             NEW.
  GPGME_ENCRYPT_THROW_KEYIDS       NEW.
  GPGME_ENCRYPT_WRAP               NEW.
  GPGME_DECRYPT_VERIFY             NEW.
  GPGME_DECRYPT_UNWRAP             NEW.
  gpgme_data_rewind                UN-DEPRECATE.
  cpp: Context::revUid(const Key&, const char*)      NEW.
  cpp: Context::startRevUid(const Key&, const char*) NEW.
  cpp: Context::addUid(const Key&, const char*)      NEW.
  cpp: Context::startAddUid(const Key&, const char*) NEW.
  cpp: Key::UserID::revoke()                         NEW.
  cpp: Key::addUid()                                 NEW.
  cpp: Key::isDeVs                                   NEW.
  cpp: GpgGenCardKeyInteractor                       NEW.
  cpp: Subkey::keyGrip                               NEW.
  cpp: Subkey::isDeVs                                NEW.
  cpp: Data::toKeys                                  NEW.
  cpp: Context::setDecryptFlags                      NEW.
  cpp: Context::decrypt                         EXTENDED: Flags added.
  cpp: Context::startDecrypt                    EXTENDED: Flags added.
  cpp: Context::decryptAndVerify                EXTENDED: Flags added.
  cpp: Context::startCombinedDecryptionAndVerification EXTENDED: Flags.
  cpp: Context::encryptFlags                    EXTENDED: New flags.
  qt: CryptoConfig::stringValueList()                NEW.
  py: Context.__init__        EXTENDED: New keyword arg home_dir.
  py: Context.home_dir        NEW.
  py: Context.keylist         EXTENDED: New keyword arg mode.
  py: Context.keylist         EXTENDED: New keyword arg source.
  py: Context.create_key      NEW.
  py: Context.create_subkey   NEW.
  py: Context.key_add_uid     NEW.
  py: Context.key_revoke_uid  NEW.
  py: Context.key_sign        NEW.
  py: Context.key_tofu_policy NEW.
  py: core.pubkey_algo_string NEW.
  py: core.addrspec_from_uid  NEW.
 
  [c=C29/A18/R0 cpp=C10/A4/R0 qt=C9/A2/R0]
 
 
 Noteworthy changes in version 1.8.0 (2016-11-16)
 ------------------------------------------------
 
  * The module of the Python bindings has been renamed to 'gpg'.
 
  * New interface to query current software versions.
 
  * New feature to use gpg's --{show,override}session-key options.
 
  * New interface to set the sender of a mail.
 
  * qt: Added Distinguished Name parser from libkleo
 
  * The --homedir option is now used with recent gpgconf versions.
 
  * On 64 bit Windows systems gpgconf is now properly located.
 
  * The internal locking functions have been replaced by libgpg-error
    locking functions.
 
  * Interface changes relative to the 1.7.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_set_sender                NEW.
  gpgme_get_sender                NEW.
  gpgme_op_query_swdb             NEW.
  gpgme_op_query_swdb_result      NEW.
  gpgme_query_swdb_result_t       NEW.
  gpgme_get_ctx_flag              NEW.
  gpgme_decrypt_result_t          EXTENDED: New field session_key.
  qt: DN                          NEW.
  qt: DN::Attribute               NEW.
  qt: Job::context(Job*)          NEW.
  cpp: EngineInfo::Version::Version(const char*) NEW.
  cpp: EngineInfo::Version::Version()            NEW.
  cpp: SwdbResult                                NEW.
  cpp: Context::setSender(const char*)           NEW.
  cpp: Context::getSender()                      NEW.
 
  [c=C28/A17/R0 cpp=C9/A3/R0 qt=C8/A1/R0]
 
 
 Noteworthy changes in version 1.7.1 (2016-10-18)
 ------------------------------------------------
 
  * Fixed problems with the new language bindings.
 
  * New helper function gpgme_addrspec_from_uid.
 
  * Use option --exit-on-status-write-error with newer gpg versions.
 
  * qt: Missed API from the Qt Binding inclusion has
    been added again.
 
  * qt: abstractimportjob.h is now installed to that
    ImportJobs can be used again.
 
  * qt: Fixed spelling error in API (startReceive).
 
  * Interface changes relative to the 1.7.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_addrspec_from_uid         NEW.
  qt: WksPublishJob::startRecieve RENAMED to ::startReceive.
  qt: MultiDeleteJob              NEW.
  qt: AbstractImportJob           NEW.
  qt: SpecialJob                  NEW.
  cpp: Signature::key(bool, bool)              NEW.
  cpp: UserID::addrSpecFromString(const char*) NEW.
  cpp: UserID::addrSpec()                      NEW.
 
  [c=C27/A16/R0 cpp=C8/A2/R0 qt=C7/A0/R0]
 
 
 Noteworthy changes in version 1.7.0 (2016-09-21)
 ------------------------------------------------
 
  * New language bindings for Python 2 and 3.
 
  * New language Bindings for C++ and the Qt-Framework API.
 
  * New functions gpgme_op_createkey and gpgme_op_createsubkey to make
    key creation easier (requires GnuPG 2.1).
 
  * New functions gpgme_op_adduid and gpgme_op_revuid to make user id
    management easier (requires GnuPG 2.1).
 
  * New function gpgme_op_keysign to make key signing easier (requires
    GnuPG 2.1).
 
  * New function gpgme_op_interact to replace the now deprecated
    functions gpgme_op_edit and gpgme_op_card_edit.
 
  * New function gpgme_pubkey_algo_string to convert a public key
    algorithm into a GnuPG 2.1 style string.
 
  * Support for GnuPG 2.1's TOFU trust model.
 
  * Notation flags are now correctly set on verify.
 
  * New global flag "require-gnupg" to set a minimal gnupg version.
 
  * More supported items in gpgme_get_dirinfo.
 
  * New function gpgme_data_set_flag and flag "size-hint".
 
  * New function gpgme_set_ctx_flag and flags "full-status" and
    "raw-description".
 
  * Improved gpgme_data_identify to distinguish more file types.
 
  * New flag GPGME_ENCRYPT_SYMMETRIC for gpgme_op_encrypt to allow
    mixed public key and symmetric encryption.
 
  * New field KEYGRIP in gpgme_subkey_t.  New fields FPR in gpgme_key_t.
 
  * New flag GPGME_DATA_ENCODING_MIME to declare that the encrypted or
    signed data is a valid MIME part.  This is to support future GnuPG
    versions.
 
  * Interface changes relative to the 1.6.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_pubkey_algo_string       NEW.
  GPGME_PK_EDDSA                 NEW.
  gpgme_set_ctx_flag             NEW.
  gpgme_data_set_flag            NEW.
  gpgme_op_createkey             NEW.
  gpgme_op_createkey_start       NEW.
  gpgme_op_createsubkey          NEW.
  gpgme_op_createsubkey_start    NEW.
  gpgme_op_adduid_start          NEW.
  gpgme_op_adduid                NEW.
  gpgme_op_revuid_start          NEW.
  gpgme_op_revuid                NEW.
  gpgme_op_keysign_start         NEW.
  gpgme_op_keysign               NEW.
  gpgme_op_tofu_policy_start     NEW.
  gpgme_op_tofu_policy           NEW.
  gpgme_op_interact_start        NEW.
  gpgme_op_interact              NEW.
  gpgme_interact_cb_t            NEW.
  gpgme_op_edit_start            DEPRECATED.
  gpgme_op_edit                  DEPRECATED.
  gpgme_op_card_edit_start       DEPRECATED.
  gpgme_op_card_edit             DEPRECATED.
  gpgme_edit_cb_t                DEPRECATED.
  gpgme_status_code_t            DEPRECATED.
  gpgme_genkey_result_t          EXTENDED: New fields pubkey and seckey.
  gpgme_signature_t              EXTENDED: New field key.
  gpgme_key_t                    EXTENDED: New field fpr.
  gpgme_subkey_t                 EXTENDED: New field keygrip.
  gpgme_user_id_t                EXTENDED: New field tofu.
  gpgme_tofu_policy_t            NEW.
  gpgme_tofu_info_t              NEW.
  GPGME_STATUS_KEY_CONSIDERED    NEW.
  GPGME_STATUS_TOFU_USER         NEW.
  GPGME_STATUS_TOFU_STATS        NEW.
  GPGME_STATUS_TOFU_STATS_LONG   NEW.
  GPGME_STATUS_NOTATION_FLAGS    NEW.
  GPGME_KEYLIST_MODE_WITH_TOFU   NEW.
  GPGME_DATA_TYPE_PGP_ENCRYPTED  NEW.
  GPGME_DATA_TYPE_PGP_SIGNATURE  NEW.
  GPGME_DATA_ENCODING_MIME       NEW.
  GPGME_ENCRYPT_SYMMETRIC        NEW.
  GPGME_CREATE_SIGN              NEW.
  GPGME_CREATE_ENCR              NEW.
  GPGME_CREATE_CERT              NEW.
  GPGME_CREATE_AUTH              NEW.
  GPGME_CREATE_NOPASSWD          NEW.
  GPGME_CREATE_SELFSIGNED        NEW.
  GPGME_CREATE_NOSTORE           NEW.
  GPGME_CREATE_WANTPUB           NEW.
  GPGME_CREATE_WANTSEC           NEW.
  GPGME_CREATE_FORCE             NEW.
  GPGME_KEYSIGN_LOCAL            NEW.
  GPGME_KEYSIGN_LFSEP            NEW.
  GPGME_INTERACT_CARD            NEW.
 
  [c=C26/A15/R0 cpp=C6/A0/R1 qt=C6/A0/R1]
 
 
 Noteworthy changes in version 1.6.0 (2015-08-26) [C25/A14/R0]
 ------------------------------------------------
 
  * Added gpgme_set_offline to do a key listinging w/o requiring CRL.
 
  * Added gpgme_set_status_cb to allow a user to see some status
    messages.
 
  * Added an export mode for secret keys.
 
  * More precise error codes are returned if GnuPG >= 2.1.8 is used.
 
  * The passphrase handler for the loopback mode has been improved and may
    also be used with genkey.
 
  * [w32] The standard GnuPG 2.1 install directory is now searched for
    gpgconf.exe before a registry specified directory and the Gpg4win
    install directory.
 
  * [w32] gpgme-w32spawn.exe will now only be searched in the gpgme DLL
    directory.
 
  * Interface changes relative to the 1.5.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_set_offline              NEW.
  gpgme_get_offline              NEW.
  gpgme_set_status_cb            NEW.
  gpgme_get_status_cb            NEW.
  GPGME_EXPORT_MODE_SECRET       NEW
  GPGME_EXPORT_MODE_RAW          NEW.
  GPGME_EXPORT_MODE_PKCS12       NEW.
 
 
 Noteworthy changes in version 1.5.5 (2015-06-08) [C24/A13/R4]
 ------------------------------------------------
 
  * Fixed crash in key listings for user ids with a backslash.
 
  * Fixed regression for GPGSM use with GnuPG < 2.1.
 
  * Properly set signature summary for revoked OpenPGP keys.
 
 
 Noteworthy changes in version 1.5.4 (2015-04-13) [C24/A13/R3]
 ------------------------------------------------
 
  * Fixed a possible crash in the debug code.
 
  * Fixed building for Windows with newer versions of Mingw.
 
 
 Noteworthy changes in version 1.5.3 (2014-12-11) [C24/A13/R2]
 -------------------------------------------------------------
 
  * The export key functions do now return an error if used with the
    latest GnuPG version.
 
 
 Noteworthy changes in version 1.5.2 (2014-11-21) [C24/A13/R1]
 -------------------------------------------------------------
 
  * gpgme-tool is now installed.
 
  * Fix external listing for modern keyservers.
 
  * Minor other fixes.
 
 
 Noteworthy changes in version 1.5.1 (2014-07-30) [C24/A13/R0]
 -------------------------------------------------------------
 
  * Fixed possible overflow in gpgsm and uiserver engines.
    [CVE-2014-3564]
 
  * Added support for GnuPG 2.1's --with-secret option.
 
  * Interface changes relative to the 1.5.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_KEYLIST_MODE_WITH_SECRET NEW.
 
 
 Noteworthy changes in version 1.5.0 (2014-05-21) [C23/A12/R0]
 -------------------------------------------------------------
 
  * On Unices the engine file names are not not anymore hardwired but
    located via the envvar PATH.  All options to set the name of the
    engines for the configure run are removed.
 
  * If GPGME finds the gpgconf binary it defaults to using gpg2 or
    whatever gpgconf tells as name for the OpenPGP engine.  If gpgconf
    is not found, GPGME looks for an engine named "gpg".
 
  * New feature to use the gpgme I/O subsystem to run arbitrary
    commands.
 
  * New flag to use encryption without the default compression step.
 
  * New function to access "gpg-conf --list-dirs"
 
  * New configure option --enable-fixed-path for use by Android.
 
  * Support ECC algorithms.
 
  * Interface changes relative to the 1.4.3 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_get_dirinfo              NEW.
  gpgme_op_spawn_start           NEW.
  gpgme_op_spawn                 NEW.
  GPGME_PROTOCOL_SPAWN           NEW.
  GPGME_SPAWN_DETACHED           NEW.
  GPGME_SPAWN_ALLOW_SET_FG       NEW.
  GPGME_ENCRYPT_NO_COMPRESS      NEW.
  GPGME_PK_ECC                   NEW.
  GPGME_MD_SHA224                NEW.
  gpgme_subkey_t                 EXTENDED: New field curve.
  GPGME_STATUS_PLAINTEXT_LENGTH  NEW.
  GPGME_STATUS_MOUNTPOINT        NEW.
  GPGME_STATUS_PINENTRY_LAUNCHED NEW.
  GPGME_STATUS_ATTRIBUTE         NEW.
  GPGME_STATUS_BEGIN_SIGNING     NEW.
  GPGME_STATUS_KEY_NOT_CREATED   NEW.
 
 
 Noteworthy changes in version 1.4.3 (2013-08-12) [C22/A11/R0]
 -------------------------------------------------------------
 
  * The default engine names are now taken from the output of gpgconf.
    If gpgconf is not found the use of gpg 1 is assumed.
 
  * Under Windows the default engines names are first searched in the
    installation directory of the gpgme DLL.
 
  * New function gpgme_data_identify to detect the type of a message.
 
  * Interface changes relative to the 1.4.2 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_signers_count            NEW.
  gpgme_data_type_t              NEW.
  gpgme_data_identify            NEW.
 
 
 Noteworthy changes in version 1.4.2 (2013-05-28) [C21/A10/R0]
 -------------------------------------------------------------
 
  * Allow symmetric encryption with gpgme_op_encrypt_sign.
 
  * Fixed mismatching off_t definitions on Windows.
 
  * Interface changes relative to the 1.4.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_off_t                    NEW.
  gpgme_size_t                   NEW.
  GPGME_PROTOCOL_OPENPGP         NEW alias.
 
 
 Noteworthy changes in version 1.4.1 (2013-05-01) [C20/A9/R1]
 ------------------------------------------------------------
 
  * Fixed reading of gpg.conf files with excessive use of the group
    option.
 
  * Fixed building with the i686-w64-mingw32 toolchain.
 
  * Disabled FD passing by default for Apple.
 
 
 Noteworthy changes in version 1.4.0 (2013-02-26) [C20/A9/R0]
 ------------------------------------------------------------
 
  * New function gpgme_set_global_flag to help debugging on Android.
 
  * New function gpgme_io_writen as a convenience wrapper around
    gpgme_io_write.
 
  * New functions to support the pinentry mode feature of GnuPG 2.1.
 
  * New macro GPGME_VERSION_NUMBER to allow supporting different API
    versions without the need for a configure test.
 
  * Several improvements for gpgme-tool.
 
  * Better logging of the common "invalid engine" error code.
 
  * Support for FD passing is now enabled by default.  The configure
    option --disable-fd-passing may be used to disable this.
 
  * Interface changes relative to the 1.3.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_VERSION_NUMBER           NEW.
  gpgme_io_writen                NEW.
  gpgme_set_global_flag          NEW.
  gpgme_set_pinentry_mode        NEW.
  gpgme_get_pinentry_mode        NEW.
  gpgme_pinentry_mode_t          NEW.
  GPGME_PINENTRY_MODE_DEFAULT    NEW.
  GPGME_PINENTRY_MODE_ASK        NEW.
  GPGME_PINENTRY_MODE_CANCEL     NEW.
  GPGME_PINENTRY_MODE_ERROR      NEW.
  GPGME_PINENTRY_MODE_LOOPBACK   NEW.
 
 
 Noteworthy changes in version 1.3.2 (2012-05-02)
 ------------------------------------------------
 
  * Remove support for libgpgme-pth.  As far as we know, this was never used,
    and GnuPG is going to use our own npth in the future.
 
  * Fix signature summary information for a missing X.509 key.
 
  * Fix parsing of dates >= year 2038.
 
 
 Noteworthy changes in version 1.3.1 (2011-06-16)
 ------------------------------------------------
 
  * Ported to Windows CE.
 
  * Detect GPG versions not supporting ---passwd.
 
  * Interface changes relative to the 1.3.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_EXPORT_MODE_MINIMAL      NEW
  GPGME_STATUS_SUCCESS		NEW
  gpgme_err_code_from_syserror   NEW
  gpgme_err_set_errno            NEW
  gpgme_error_from_errno		CHANGED: Return gpgme_error_t (compatible type).
  gpgme_error_from_syserror      NEW
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.3.0 (2010-01-11)
 ------------------------------------------------
 
  * GPGME does not come with an internal libassuan version anymore.
    The external libassuan 1.1.0 release or later is required.  For
    application programmers on systems that can resolve inter-library
    dependencies at runtime, this is a transparent change.
 
  * New engine GPGME_PROTOCOL_G13 to support the new g13 tool.
 
  * New engine GPGME_PROTOCOL_UISERVER to support UI Servers.
 
  * New API to change the passphrase of a key.
 
  * Interface changes relative to the 1.2.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_STATUS_INV_SGNR    NEW.
  GPGME_STATUS_NO_SGNR     NEW.
  GPGME_PROTOCOL_G13	  NEW.
  gpgme_op_g13_mount	  NEW.
  gpgme_g13_result_t	  NEW.
  GPGME_PK_ECDSA           NEW.
  GPGME_PK_ECDH            NEW.
  gpgme_op_passwd_start    NEW.
  gpgme_op_passwd          NEW.
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.2.0 (2009-06-18)
 ------------------------------------------------
 
  * New encryption flag GPGME_ENCRYPT_NO_ENCRYPT_TO to disable default
    recipients.
 
  * gpgme_new will fail if gpgme_check_version was not called, or a
    selftest failed (for example, if -mms-bitfields was not used on
    MingW32 targets).
 
  * New functions gpgme_io_read and gpgme_io_write for use with
    gpgme_passphrase_cb_t and gpgme_edit_cb_t functions.
 
  * New functions gpgme_result_ref and gpgme_result_unref to detach
    result structures from a context.
 
  * New functions gpgme_op_export_keys_start and gpgme_op_export_keys
    that allow to specify exported keys through gpgme_key_t objects
    instead of patterns.
 
  * New mode of operation gpgme_export_mode_t that allows exporting
    external keys.
 
  * Interface changes relative to the 1.1.7 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  GPGME_KEYLIST_MODE_EPHEMERAL   NEW.
  GPGME_PROTOCOL_ASSUAN          NEW.
  gpgme_assuan_data_cb_t         NEW.
  gpgme_assuan_inquire_cb_t      NEW.
  gpgme_assuan_status_cb_t       NEW.
  gpgme_op_assuan_transact_start NEW.
  gpgme_op_assuan_transact       NEW.
  gpgme_op_assuan_result         NEW.
  gpgme_op_import_keys           NEW.
  gpgme_op_import_keys_start     NEW.
  gpgme_subkey_t                 EXTENDED: New fields is_cardkey, card_number.
  GPGME_ENCRYPT_NO_ENCRYPT_TO    NEW.
  gpgme_check_version            CHANGED: Is now a macro.
  gpgme_new                      EXTENDED: More failure codes.
  gpgme_io_read                  NEW.
  gpgme_io_write                 NEW.
  gpgme_result_ref               NEW.
  gpgme_result_unref             NEW.
  gpgme_export_mode_t            NEW.
  gpgme_export_ext_start         EXTENDED: Arg RESERVED is now a MODE flag.
  gpgme_op_export                EXTENDED: Arg RESERVED is now a MODE flag.
  gpgme_op_export_ext_start      EXTENDED: Arg RESERVED is now a MODE flag.
  gpgme_op_export_ext            EXTENDED: Arg RESERVED is now a MODE flag.
  gpgme_op_export_keys_start     NEW.
  gpgme_op_export_keys           NEW.
  GPGME_DATA_ENCODING_URL        NEW.
  GPGME_DATA_ENCODING_URL0       NEW.
  GPGME_DATA_ENCODING_URLESC     NEW.
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.1.8 (2008-12-08)
 ------------------------------------------------
 
  * SIGPIPE is now again ignored as described in the manual.  Fixes
    regression introduced with 1.1.6.
 
 
 Noteworthy changes in version 1.1.7 (2008-10-17)
 ------------------------------------------------
 
  * Using GPGME_KEYLIST_MODE_LOCAL combined with
    GPGME_KEYLIST_MODE_EXTERN is now supported; it uses the
    --locate-keys feature of gpg (>= 2.0.10).
 
  * The encoding of gpgme_data_t objects can affect the output encoding
    of export, sign and encrypt operations now (the same operations
    that are also affected by the ASCII mode switch).  We believe this
    change in the ABI is innocent enough not to break existing
    applications (it only affects the S/MIME backend on certain
    operations).
 
  * The reference manual now includes the specification of "The GnuPG
    UI Server protocol".
 
  * A new function gpgme_cancel_async can be used to asynchronously
    cancel any pending operation at any time, from any thread.
 
  * Interface changes relative to the 1.1.6 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_op_encrypt		CHANGED: Output encoding can affect result.
 gpgme_op_encrypt_start		CHANGED: Output encoding can affect result.
 gpgme_op_encrypt_sign		CHANGED: Output encoding can affect result.
 gpgme_op_encrypt_sign_start	CHANGED: Output encoding can affect result.
 gpgme_op_sign			CHANGED: Output encoding can affect result.
 gpgme_op_sign_start		CHANGED: Output encoding can affect result.
 gpgme_op_export			CHANGED: Output encoding can affect result.
 gpgme_op_export_start		CHANGED: Output encoding can affect result.
 gpgme_op_export_ext		CHANGED: Output encoding can affect result.
 gpgme_op_export_ext_start	CHANGED: Output encoding can affect result.
 gpgme_cancel_async		NEW
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.1.6 (2008-01-04)
 ------------------------------------------------
 
  * Bug fixes for for W32.
 
  * A new, experimental (and thus undocumented and potentially
    unstable) interface for accessing gpg-conf through GPGME has been
    added.
 
  * Interface changes relative to the 1.1.1 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_signature_t               EXTENDED: New field chain_model.
  gpgme_op_getauditlog_start      NEW.
  gpgme_op_getauditlog            NEW.
  GPGME_AUDITLOG_HTML             NEW.
  GPGME_AUDITLOG_WITH_HELP        NEW.
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.1.5 (2007-07-09)
 ------------------------------------------------
 
  * Bug and portability fixes (mainly for W32).
 
 
 Noteworthy changes in version 1.1.4 (2007-03-05)
 ------------------------------------------------
 
  * Detect and bail out on double plaintext messages.  This is required
    so that applications can properly detect the signed parts of a
    message.  Actual there is now a double protection as GnuPG 1.4.7
    will detect this case too.
 
 
 Noteworthy changes in version 1.1.3 (2007-01-29)
 ------------------------------------------------
 
  * Fixed a memory leak in gpgme_data_release_and_get_mem.
 
  * Fixed a bug in Windows command line quoting.
 
 
 Noteworthy changes in version 1.1.2 (2006-03-02)
 ------------------------------------------------
 
  * Fixed a bug in the W32 glib backend.
 
 
 Noteworthy changes in version 1.1.1 (2006-02-23)
 ------------------------------------------------
 
  * Fixed a bug in that the fingerprints of subkeys are not available.
 
  * Clarified usage of the SECRET flag in key listings.  It is now
    reset for stub keys.
 
  * Reading signature notations and policy URLs on key signatures is
    supported.  They can be found in the new field notations of the
    gpgme_key_sig_t structure.  This has to be enabled with the keylist
    mode flag GPGME_KEYLIST_MODE_SIG_NOTATIONS.
 
  * A new gpgme_free() function solves the problem of using different
    allocators in a single program.  This function should now be used
    instead calling free() to release the buffer returned by
    gpgme_data_release_and_get_mem.  It is recommended that you always
    do this, but it is only necessary on certain platforms, so backwards
    compatibility is provided.  In other words: If free() worked for
    you before, it will keep working.
 
  * New status codes GPGME_PKA_TRUST_GOOD and GPGME_PKA_TRUST_BAD.
    They are analyzed by the verify handlers and made available in the
    new PKA_TRUST and PKA_ADDRESS fields of the signature result structure.
 
  * Interface changes relative to the 1.1.0 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_key_sig_t			EXTENDED: New field notations.
 GPGME_KEYLIST_MODE_SIG_NOTATIONS NEW
 gpgme_free			NEW
 GPGME_STATUS_PKA_TRUST_BAD      NEW
 GPGME_STATUS_PKA_TRUST_GOOD     NEW
 gpgme_signature_t               EXTENDED: New field pka_trust.
 gpgme_signature_t               EXTENDED: New field pka_address.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.1.0 (2005-10-01)
 ------------------------------------------------
 
  * You can now configure the backend engine file name and home
    directory to be used, as default and per context.
 
  * Information about the recipients of an encrypted text is now
    available at decryption time.
 
  * New status GPGME_STATUS_PLAINTEXT.  This is analyzed by the decrypt
    and verify handlers, the information about the plaintext filename,
    if available is made available in the new field file_name of the
    respective result structure.
 
  * The code for "automagically detecting the thread library" has been
    removed from libgpgme.  It is deprecated since version 0.4.3.
    Since then, you had to link against libgpgme-pthread for
    applications using pthread and libgpgme-pth for applications using
    GNU Pth.
 
    The code was removed because it caused compilation problems on
    systems where the pthread.h header from GNU Pth is available in
    addition to the system header (FreeBSD 6 and later for example).
 
  * "./autogen.sh --build-w32" does now build gpgme.dll.
 
  * [W32] The environment variable GPGME_DEBUG now uses a semicolon as
    delimiter.  The standard install directory is used when locating
    gpg or gpgsm before finally falling back to the hardwired name.
 
  * There is a new flag for keys and subkeys, is_qualified, which
    indicates if a key can be used for qualified signatures according
    to local government regulations.
 
  * You can associate a filename with a data object using the new
    function gpgme_data_set_file_name().  This filename will be stored
    in the output when encrypting or signing the data and will be
    returned when decrypting or verifying the output data.
 
  * You can now set notation data at signature creation with the new
    function gpgme_sig_notation_add().
 
  * Interface changes relative to the 1.0.3 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_set_engine_info		NEW
 gpgme_ctx_get_engine_info	NEW
 gpgme_ctx_set_engine_info	NEW
 gpgme_recipient_t		NEW
 gpgme_decrypt_result_t		EXTENDED: New field recipients.
 gpgme_verify_result_t		EXTENDED: New fields pubkey_algo, hash_algo.
 gpgme_decrypt_result_t		EXTENDED: New field plaintext_filename.
 gpgme_verify_result_t		EXTENDED: New field plaintext_filename.
 GPGME_STATUS_PLAINTEXT		NEW
 gpgme_key_t			EXTENDED: New field is_qualified.
 gpgme_subkey_t			EXTENDED: New field is_qualified.
 gpgme_data_get_file_name	NEW
 gpgme_data_set_file_name	NEW
 gpgme_sig_notation_flags_t	NEW
 GPGME_SIG_NOTATION_HUMAN_READABLE NEW
 GPGME_SIG_NOTATAION_CRITICAL	NEW
 gpgme_sig_notation_clear	NEW
 gpgme_sig_notation_add		NEW
 gpgme_sig_notation_get		NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.0.3 (2005-06-20)
 ------------------------------------------------
 
  * Previousy, GPGME would use a default "include certs" of 1.  This
    has been changed.  Now GPGME will use the crypto backend engines
    default unless you set the value with gpgme_set_include_certs()
    explicitly.  A new macro GPGME_INCLUDE_CERTS_DEFAULT can be used
    as a value to explicitly request the new default behaviour.
 
    Because the default changes, this is a slight change of the API
    semantics.  We consider it to be a bug fix.
 
  * A bug which made GPGME hang has been fixed.  If you have
    experienced hanging before, please try out this version and let me
    know if you still experience hanging problems.
 
  * Interface changes relative to the 0.9.0 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_set_include_certs		CHANGED DEFAULT
 GPGME_INCLUDE_CERTS_DEFAULT	NEW
 GPGME_STATUS_SIG_SUBPACKET	NEW
 GPGME_STATUS_NEED_PASSPHRASE_PIN NEW
 GPGME_STATUS_SC_OP_FAILURE	NEW
 GPGME_STATUS_SC_OP_SUCCESS	NEW
 GPGME_STATUS_CARDCTRL		NEW
 GPGME_STATUS_BACKUP_KEY_CREATED	NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 1.0.2 (2004-12-28)
 ------------------------------------------------
 
  * Changed the license of the library to the GNU Lesser General Public
    License (LGPL), version 2.1 or later.
 
 
 Noteworthy changes in version 1.0.1 (2004-10-22)
 ------------------------------------------------
 
  * Only bug fixes.
 
 
 Noteworthy changes in version 1.0.0 (2004-09-30)
 ------------------------------------------------
 
  * Version 1.0.0!  We are proud to present you with a thoroughly
    tested and stable version of the GPGME library.  A big Thank You!
    to all the people who made this possible.
 
    The development will be branched into a stable 1.x.y series and the
    head.
 
  * The gpgme.m4 macro supports checking the API version.  Just prepend
    it to the required version string, separated by a colon.  For
    example, this release has the version "1:1.0.0".  The last release
    to which this version is (mostly) ABI compatible is "1:0.4.2",
    which is the default required version.
 
 
 Noteworthy changes in version 0.9.0 (2004-06-08)
 ------------------------------------------------
 
  * The type gpgme_key_t has now a new field keylist_mode that contains
    the keylist mode that was active at the time the key was retrieved.
 
  * The type gpgme_decrypt_result_t has a new field "wrong_key_usage"
    that contains a flag indicating that the key should not have been
    used for encryption.
 
  * Verifying a signature of a revoked key gives the correct result now
    (GPG_ERR_CERT_REVOKED error code).
 
  * Clarified that the error code GPG_ERR_NO_DATA from the decrypt &
    verify operations still allows you to look at the signature
    verification result.
 
  * Clarified that patterns in keylisting operations have an upper
    limit, and thus are not suited to list many keys at once by their
    fingerprint.  Also improve the error message if the pattern is too
    long for the CMS protocol to handle.
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_key_t			EXTENDED: New field keylist_mode.
 gpgme_decrypt_result_t		EXTENDED: New field wrong_key_usage.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 0.4.7 (2004-04-29)
 ------------------------------------------------
 
  * Correctly initialize the fields expired, revoked, invalid, and
    disabled in the gpgme_key_t structures.
 
  * A bug fix: The flag wrong_key_usage of gpgme_signature_t was
    accidentally of type int instead unsigned int.
 
  * Interface changes relative to the 0.4.5 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_signature_t		CHANGED: wrong_key_usage is unsigned int now.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.4.6 (2004-04-06)
 ------------------------------------------------
 
  * Bug fixes
 
 
 Noteworthy changes in version 0.4.5 (2004-03-07)
 ------------------------------------------------
 
  * GPGME is now compiled with LFS (large file support) by default.
    This means that _all_ programs using GPGME must be compiled with
    LFS support enabled by default.  You can do this easily with
    autoconf, by using the AC_SYS_LARGEFILE macro.  Or you can do this
    without autoconf by defining the preprocessor symbol
    _FILE_OFFSET_BITS to 64 (by passing the -D_FILE_OFFSET_BITS=64 to
    the C compiler command line, or by defining this preprocessor
    symbol before including any system header files).  For more
    details, read the section on LFS in the manual.
 
    Up to now, it was undocumented that GPGME was not using LFS.
    But the public interfaces use off_t, and file descriptors are
    exchanged between the application and GPGME.  This was an oversight,
    and bound to cause troubles in the future.
 
    Writing GPGME as a dual mode library that seamlessly supports LFS
    while keeping backwards compatibility is possible, but does not
    solve the problem: Many applications already expect GPGME to have
    LFS (they are compiled with off_t being a 64bit value).  This is true
    in particular for the popular Gtk+ and Qt programs.
 
    So, although this is an ABI (but not an API) break, we will not
    change the library version to reflect that.  Because the interfaces
    affected are probably not used yet in any GPGME 0.4 based
    application, we don't expect any real failures from this change.
    In fact, applications already using LFS will have some subtle bugs
    fixed.
 
    However, if you encounter an application using GPGME 0.4.x that
    does _not_ use LFS by default (off_t is a 32bit value), _and_
    uses at least one of the functions gpgme_data_seek,
    gpgme_data_new_from_filepart, or a gpgme_data_seek_cb_t with
    gpgme_data_new_from_cbs, then indeed this library will be ABI
    incompatible with the program.  As said above, we don't believe
    such a program exists.  If we are in error, then you have two
    options: As a quick hack, you can configure GPGME with the
    --disable-largefile option.  This will revert the change, and GPGME
    will not use LFS.  However, GPGME will be incompatible with
    programs that expect GPGME to use LFS.  All applications are
    required to use LFS when using GPGME, so this is only good as a
    temporary local work-around.
 
    The other option is to change the versioning of the library and
    recompile all applications.  We have reserved a special version of
    the library for that, so you can do that without expecting a
    version clash in the future.  Furthermore, everyone who does this
    will agree on the version to use (this is important for
    distribution makers).  Read the comment in configure.ac (before
    LIBGPGME_LT_AGE) if you want to do this.  Please don't do this
    blindly: As stated above, we think it is unlikely this measure is
    needed.  Still, it is there if necessary.  If in doubt, contact us
    and we will give our advise for your specific situation.
 
  * New key listing mode GPGME_KEYLIST_MODE_VALIDATE for validation of
    the listed keys.
 
  * New interface gpgme_cancel() that can be used to cancel
    asynchronous operations.
 
  * Interface changes relative to the 0.4.4 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_data_seek_cb_t		CHANGED: off_t is now a largefile type.
 gpgme_data_seek			CHANGED: off_t is now a largefile type.
 gpgme_data_new_from_filepart	CHANGED: off_t is now a largefile type.
 GPGME_KEYLIST_MODE_VALIDATE     NEW
 gpgme_cancel			NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.4.4 (2004-01-12)
 ------------------------------------------------
 
  * The member "class" in gpgme_key_sig_t and gpgme_new_signature_t has
    been renamed to "sig_class", to avoid clash with C++ compilers.  In
    the C API, the old name "class" has been preserved for backwards
    compatibility, but is deprecated.
 
  * Interface changes relative to the 0.4.3 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_key_sig_t			CHANGED: class deprecated, use new sig_class.
 gpgme_new_signature_t		CHANGED: class deprecated, use new sig_class.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.4.3 (2003-10-06)
 ------------------------------------------------
 
  * libgpgme should not be used for threaded programs anymore.  This
    never worked reliably in all cases, because you had to
    be careful about the linking order and libtool wouldn't do that for
    you automatically.  Instead, now you have to link against
    libgpgme-pthread for applications using pthread and libgpgme-pth for
    applications using GNU Pth.
 
    The old code for automagically detecting the thread library is
    still part of libgpgme, but it is DEPRECATED.
 
  * There are new automake macros AM_PATH_GPGME_PTH and
    AM_PATH_GPGME_PTHREAD, which support checking for thread-enabled
    versions of GPGME.  They define GPGME_PTH_CFLAGS, GPGME_PTH_LIBS,
    GPGME_PTHREAD_CFLAGS and GPGME_PTHREAD_LIBS respectively.  These
    variables of course also include the configuration for the thread
    package itself.  Alternatively, use libtool.
 
  * gpgme_strerror_r as a thread safe variant of gpgme_strerror was
    added.
 
  * gpgme-config doesn't support setting the prefix or exec prefix
    anymore.  I don't think it ever worked correctly, and it seems to
    be pointless.
 
  * gpgme_get_key fails with GPG_ERR_AMBIGUOUS_NAME if the key ID
    provided was not unique, instead returning the first matching key.
 
  * gpgme_key_t and gpgme_subkey_t have a new field, can_authenticate,
    that indicates if the key can be used for authentication.
 
  * gpgme_signature_t's status field is now correctly set to an error
    with error code GPG_ERR_NO_PUBKEY if public key is not found.
 
  * gpgme_new_signature_t's class field is now an unsigned int, rather
    than an unsigned long (the old class field is preserved for
    backwards compatibility).
 
  * A new function gpgme_set_locale() is provided to allow configuring
    the locale for the crypto backend.  This is necessary for text
    terminals so that programs like the pinentry can be started with
    the right locale settings for the terminal the application is running
    on, in case the terminal has different settings than the system
    default (for example, if it is a remote terminal).  You are highly
    recommended to call the following functions directly after
    gpgme_check_version:
 
    #include <locale.h>
 
    setlocale (LC_ALL, "");
    gpgme_set_locale (NULL, LC_CTYPE, setlocale (LC_CTYPE, NULL));
    gpgme_set_locale (NULL, LC_MESSAGES, setlocale (LC_MESSAGES, NULL));
 
    GPGME can not do this for you, as setlocale is not thread safe, and
    there is no alternative.
 
  * The signal action for SIGPIPE is now set to SIG_IGN by
    gpgme_check_version, instead the first time a crypto engine is
    started (which is not well defined).
 
  * In the output of gpgme_hash_algo_name, change RMD160 to RIPEMD160,
    TIGER to TIGER192, CRC32-RFC1510 to CRC32RFC1510, and CRC24-RFC2440
    to CRC24RFC2440.  For now, these strings can be used as the MIC
    parameter for PGP/MIME (if appropriately modified).
 
  * Interface changes relative to the 0.4.2 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_strerror_t		NEW
 gpgme_get_key			CHANGED: Fails correctly if key ID not unique.
 gpgme_key_t			EXTENDED: New field can_authenticate.
 gpgme_subkey_t			EXTENDED: New field can_authenticate.
 gpgme_new_signature_t		CHANGED: New type for class field.
 gpgme_set_locale		NEW
 gpgme_hash_algo_name		CHANGED: Slight adjustment of algo names.
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.4.2 (2003-07-30)
 ------------------------------------------------
 
  * Allow gpg-error to be in non-standard place when linking the test suite.
 
  * Configure will fail now if gpg-error can not be found.
 
  * Fixed initialized memory backed data objects for writing, which
    caused the test program to crash (but only on Mac OS, surprisingly).
 
  * Eliminate use of C99 constructs.
 
  * Small improvements to the manual.
 
 
 Noteworthy changes in version 0.4.1 (2003-06-06)
 ------------------------------------------------
 
  This is the release that 0.4.0 should have been.  There are many
  interface changes, please see below for the details.  The changes are
  sometimes the result of new functionality, but more often express a
  paradigm shift.  Others are an overdue cleanup to get GPGME in line
  with the GNU coding standards and to make the interface more
  self-consistent.  Here is an overview on the changes:
 
  All types have been renamed to conform to the GNU coding standards,
  most of the time by keeping the whole name in lowercase and inserting
  underscores between words.
 
  All operations consistently only accept input parameters in their
  invocation function, and return only an error code directly.  Further
  information about the result of the operation has to be retrieved
  afterwards by calling one of the result functions.  This unifies the
  synchronous and the asynchronous interface.
 
  The error values have been completely replaced by a more
  sophisticated model that allows GPGME to transparently and accurately
  report all errors from the other GnuPG components, regardless of
  process boundaries.  This is achieved by using the library
  libgpg-errors, which is shared by all GnuPG components.  This library
  is now required for GPGME.
 
  The results of all operations are now provided by pointers to C
  structs rather than by XML structs or in other ways.
 
  Objects which used to be opaque (for example a key) are now pointers
  to accessible structs, so no accessor functions are necessary.
 
  Backward compatibility is provided where it was possible without too
  much effort and did not collide with the overall sanitization effort.
  However, this is only for ease of transition.  NO DEPRECATED FUNCTION
  OR DATA TYPE IS CONSIDERED A PART OF THE API OR ABI AND WILL BE
  DROPPED IN THE FUTURE WITHOUT CHANGING THE SONAME OF THE LIBRARY.
  Recommendations how to replace deprecated or removed functionality
  can be found within the description of each change.
 
  What follows are all changes to the interface and behaviour of GPGME
  in detail.
 
  * If gpgme.h is included in sources compiled by GCC 3.1 or later,
    deprecated attributes will warn about use of obsolete functions and
    type definitions.  You can suppress these warnings by passing
    -Wno-deprecated-declarations to the gcc command.
 
  * The following types have been renamed.  The old types are still
    available as aliases, but they are deprecated now:
    Old name:		New name:
    GpgmeCtx		gpgme_ctx_t
    GpgmeData		gpgme_data_t
    GpgmeError		gpgme_error_t
    GpgmeDataEncoding	gpgme_data_encoding_t
    GpgmeSigStat		gpgme_sig_stat_t
    GpgmeSigMode		gpgme_sig_mode_t
    GpgmeAttr		gpgme_attr_t
    GpgmeValidity	gpgme_validity_t
    GpgmeProtocol	gpgme_protocol_t
    GpgmeKey		gpgme_key_t
    GpgmePassphraseCb	gpgme_passphrase_cb_t
    GpgmeProgressCb	gpgme_progress_cb_t
    GpgmeIOCb		gpgme_io_cb_t
    GpgmeRegisterIOCb	gpgme_register_io_cb_t
    GpgmeRemoveIOCb	gpgme_remove_io_cb_t
    GpgmeEventIO		gpgme_event_io_t
    GpgmeEventIOCb	gpgme_event_io_cb_t
    GpgmeIOCbs		gpgme_io_cbs
    GpgmeDataReadCb	gpgme_data_read_cb_t
    GpgmeDataWriteCb	gpgme_data_write_cb_t
    GpgmeDataSeekCb	gpgme_data_seek_cb_t
    GpgmeDataReleaseCb	gpgme_data_release_cb_t
    GpgmeDataCbs		gpgme_data_cbs_t
    GpgmeTrustItem	gpgme_trust_item_t
    GpgmeStatusCode	gpgme_status_code_t
 
  * gpgme_error_t is now identical to gpg_error_t, the error type
    provided by libgpg-error.  More about using libgpg-error with GPGME
    can be found in the manual.  All error symbols have been removed!
 
  * All functions and types in libgpg-error have been wrapped in GPGME.
    The new types are gpgme_err_code_t and gpgme_err_source_t.  The new
    functions are gpgme_err_code, gpgme_err_source, gpgme_error,
    gpgme_err_make, gpgme_error_from_errno, gpgme_err_make_from_errno,
    gpgme_err_code_from_errno, gpgme_err_code_to_errno,
    gpgme_strsource.
 
  * GPGME_ATTR_IS_SECRET is not anymore representable as a string.
 
  * GnuPG 1.2.2 is required.  The progress callback is now also invoked
    for encrypt, sign, encrypt-sign, decrypt, verify, and
    decrypt-verify operations.  For verify operations on detached
    signatures, the progress callback is invoked for both the detached
    signature and the plaintext message, though.
 
  * gpgme_passphrase_cb_t has been changed to not provide a complete
    description, but the UID hint, passphrase info and a flag
    indicating if this is a repeated attempt individually, so the user
    can compose his own description from this information.
 
    The passphrase is not returned as a C string, but must be written
    to a file descriptor directly.  This allows for secure passphrase
    entries.
 
    The return type has been changed to gpgme_error_t value.  This
    allowed to remove the gpgme_cancel function; just return
    the error code GPG_ERR_CANCELED in the passphrase callback directly.
 
  * gpgme_edit_cb_t has been changed to take a file descriptor argument.
    The user is expected to write the response to the file descriptor,
    followed by a newline.
 
  * The recipients interface has been removed.  Instead, you use
    NULL-terminated lists of keys for specifying the recipients of an
    encryption operation.  Use the new encryption flag
    GPGME_ENCRYPT_ALWAYS_TRUST if you want to override the validity of
    the keys (but note that in general this is not a good idea).
 
    This change has been made to the prototypes of gpgme_op_encrypt,
    gpgme_op_encrypt_start, gpgme_op_encrypt_sign and
    gpgme_op_encrypt_sign_start.
 
    The export interface has been changed to use pattern strings like
    the keylist interface.  Thus, new functions gpgme_op_export_ext and
    gpgme_op_export_ext_start have been added as well.  Now the
    prototypes of gpgme_op_export_start and gpgme_op_export finally
    make sense.
 
  * gpgme_op_verify and gpgme_op_decrypt_verify don't return a status
    summary anymore.  Use gpgme_get_sig_status to retrieve the individual
    stati.
 
  * gpgme_io_cb_t changed from a void function to a function returning
    a gpgme_error_t value.  However, it will always return 0, so you
    can safely ignore the return value.
 
  * A new I/O callback event GPGME_EVENT_START has been added.  The new
    requirement is that you must wait until this event until you are
    allowed to call the I/O callback handlers previously registered for
    this context operation.  Calling I/O callback functions for this
    context operation before the start event happened is unsafe because
    it can lead to race conditions in a multi-threaded environment.
 
  * The idle function feature has been removed.  It was not precisely
    defined in a multi-threaded environment and is obsoleted by the
    user I/O callback functions.  If you still need a simple way to
    call something while waiting on one or multiple asynchronous
    operations to complete, don't set the HANG flag in gpgme_wait (note
    that this will return to your program more often than the idle
    function did).
 
  * gpgme_wait can return NULL even if hang is true, if an error
    occurs.  In that case *status contains the error code.
 
  * gpgme_get_engine_info was radically changed.  Instead an XML
    string, an info structure of the new type gpgme_engine_info_t is
    returned.  This makes it easier and more robust to evaluate the
    information in an application.
 
  * The new function gpgme_get_protocol_name can be used to convert a
    gpgme_protocol_t value into a string.
 
  * The status of a context operation is not checked anymore.  Starting
    a new operation will silently cancel the previous one.  Calling a
    function that requires you to have started an operation before without
    doing so is undefined.
 
  * The FPR argument to gpgme_op_genkey was removed.  Instead, use the
    gpgme_op_genkey_result function to retrieve a gpgme_genkey_result_t
    pointer to a structure which contains the fingerprint.  This also
    works with gpgme_op_genkey_start.  The structure also provides
    other information about the generated keys.
 
    So, instead:
 
    char *fpr;
    err = gpgme_op_genkey (ctx, NULL, NULL, &fpr);
    if (!err && fpr)
      printf ("%s\n", fpr);
 
    you should now do:
 
    gpgme_genkey_result_t result;
    err = gpgme_op_genkey (ctx, NULL, NULL);
    if (!err)
      {
        result = gpgme_op_genkey_result (ctx);
        if (result->fpr)
          printf ("%s\n", result->fpr);
      }
 
  * The new gpgme_op_import_result function provides detailed
    information about the result of an import operation in
    gpgme_import_result_t and gpgme_import_status_t objects.
    Thus, the gpgme_op_import_ext variant is deprecated.
 
  * The new gpgme_op_sign_result function provides detailed information
    about the result of a signing operation in gpgme_sign_result_t,
    gpgme_invalid_key_t and gpgme_new_signature_t objects.
 
  * The new gpgme_op_encrypt_result function provides detailed
    information about the result of an encryption operation in
    a GpgmeEncryptResult object.
 
  * The new gpgme_op_decrypt_result function provides detailed
    information about the result of a decryption operation in
    a GpgmeDecryptResult object.
 
  * The new gpgme_op_verify_result function provides detailed
    information about the result of an verify operation in
    a GpgmeVerifyResult object.  Because of this, the GPGME_SIG_STAT_*
    values, gpgme_get_sig_status, gpgme_get_sig_ulong_attr,
    gpgme_get_sig_string_attr and gpgme_get_sig_key are now deprecated,
    and gpgme_get_notation is removed.
 
  * GpgmeTrustItem objects have now directly accessible data, so the
    gpgme_trust_item_get_string_attr and gpgme_trust_item_get_ulong_attr
    accessor functions are deprecated.  Also, reference counting is
    available through gpgme_trust_item_ref and gpgme_trust_item_unref
    (the gpgme_trust_item_release alias for the latter is deprecated).
 
  * Keys are not cached internally anymore, so the force_update argument
    to gpgme_get_key has been removed.
 
  * GpgmeKey objects have now directly accessible data so the
    gpgme_key_get_string_attr, gpgme_key_get_ulong_attr,
    gpgme_key_sig_get_string_attr and gpgme_key_sig_get_ulong_attr
    functions are deprecated.  Also, gpgme_key_release is now
    deprecated.  The gpgme_key_get_as_xml function has been dropped.
 
  * Because all interfaces using attributes are deprecated, the
    GpgmeAttr data type is also deprecated.
 
  * The new gpgme_op_keylist_result function provides detailed
    information about the result of a key listing operation in
    a GpgmeKeyListResult object.
 
  * Now that each function comes with its own result retrieval
    interface, the generic gpgme_get_op_info interface is not useful
    anymore and dropped.
 
  * The type and mode of data objects is not available anymore.
 
  * Interface changes relative to the 0.4.0 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 GpgmeCtx			DEPRECATED: Use gpgme_ctx_t.
 GpgmeData			DEPRECATED: Use gpgme_data_t.
 GpgmeError			DEPRECATED: Use gpgme_error_t.
 GpgmeDataEncoding		DEPRECATED: Use gpgme_data_encoding_t.
 GpgmeSigStat			DEPRECATED: Use gpgme_sig_stat_t.
 GpgmeSigMode			DEPRECATED: Use gpgme_sig_mode_t.
 GpgmeAttr			DEPRECATED: Use gpgme_attr_t.
 GpgmeValidity			DEPRECATED: Use gpgme_validity_t.
 GpgmeProtocol			DEPRECATED: Use gpgme_protocol_t.
 GpgmeKey			DEPRECATED: Use gpgme_key_t.
 GpgmePassphraseCb		DEPRECATED: Use gpgme_passphrase_cb_t.
 GpgmeProgressCb			DEPRECATED: Use gpgme_progress_cb_t.
 GpgmeIOCb			DEPRECATED: Use gpgme_io_cb_t.
 GpgmeRegisterIOCb		DEPRECATED: Use gpgme_register_io_cb_t.
 GpgmeRemoveIOCb			DEPRECATED: Use gpgme_remove_io_cb_t.
 GpgmeEventIO			DEPRECATED: Use gpgme_event_io_t.
 GpgmeEventIOCb			DEPRECATED: Use gpgme_event_io_cb_t.
 GpgmeIOCbs			DEPRECATED: Use gpgme_io_cbs.
 GpgmeDataReadCb			DEPRECATED: Use gpgme_data_read_cb_t.
 GpgmeDataWriteCb		DEPRECATED: Use gpgme_data_write_cb_t.
 GpgmeDataSeekCb			DEPRECATED: Use gpgme_data_seek_cb_t.
 GpgmeDataReleaseCb		DEPRECATED: Use gpgme_data_release_cb_t.
 GpgmeDataCbs			DEPRECATED: Use gpgme_data_cbs_t.
 GpgmeTrustItem			DEPRECATED: Use gpgme_trust_item_t.
 GpgmeStatusCode			DEPRECATED: Use gpgme_status_code_t.
 gpgme_ctx_t			NEW
 gpgme_data_t			NEW
 gpgme_recipients_t		NEW
 gpgme_error_t			NEW
 gpgme_data_encoding_t		NEW
 gpgme_sig_stat_t		NEW
 gpgme_sig_mode_t		NEW
 gpgme_attr_t			NEW
 gpgme_validity_t		NEW
 gpgme_protocol_t		NEW
 gpgme_key_t			NEW
 gpgme_passphrase_cb_t		NEW
 gpgme_progress_cb_t		NEW
 gpgme_io_cb_t			NEW
 gpgme_register_io_cb_t		NEW
 gpgme_remove_io_cb_t		NEW
 gpgme_event_io_t		NEW
 gpgme_event_io_cb_t		NEW
 gpgme_io_cbs			NEW
 gpgme_data_read_cb_t		NEW
 gpgme_data_write_cb_t		NEW
 gpgme_data_seek_cb_t		NEW
 gpgme_data_release_cb_t		NEW
 gpgme_data_cbs_t		NEW
 gpgme_trust_item_t		NEW
 gpgme_status_code_t		NEW
 GPGME_{some error code}		REMOVED! Use GPG_ERR_* from libgpg-error.
 gpgme_err_code_t		NEW
 gpgme_err_source_t		NEW
 gpgme_err_code			NEW
 gpgme_err_source		NEW
 gpgme_error			NEW
 gpgme_err_make			NEW
 gpgme_error_from_errno		NEW
 gpgme_err_make_from_errno	NEW
 gpgme_err_code_from_errno	NEW
 gpgme_err_code_to_errno		NEW
 gpgme_strsource			NEW
 gpgme_io_cb_t			CHANGED: Return type from void to GpgmeError.
 gpgme_event_io_t		CHANGED: New event type (all numbers changed).
 gpgme_passphrase_cb_t		CHANGED: Desc decomposed, write directly to FD.
 gpgme_edit_cb_t			CHANGED: Write directly to FD.
 gpgme_key_get_string_attr	CHANGED: Don't handle GPGME_ATTR_IS_SECRET.
 gpgme_op_verify			CHANGED: Drop R_STAT argument.
 gpgme_op_decrypt_verify		CHANGED: Drop R_STAT argument.
 gpgme_wait			CHANGED: Can return NULL even if hang is true.
 GpgmeIdleFunc                   REMOVED
 gpgme_register_idle             REMOVED
 GpgmeRecipients			REMOVED
 gpgme_recipients_new		REMOVED
 gpgme_recipients_release	REMOVED
 gpgme_recipients_add_name	REMOVED
 gpgme_recipients_add_name_with_validity	REMOVED
 gpgme_recipients_count		REMOVED
 gpgme_recipients_enum_open	REMOVED
 gpgme_recipients_enum_read	REMOVED
 gpgme_recipients_enum_close	REMOVED
 gpgme_encrypt_flags_t		NEW
 GPGME_ENCRYPT_ALWAYS_TRUST	NEW
 gpgme_op_encrypt		CHANGED: Recipients passed as gpgme_key_t[].
 gpgme_op_encrypt_start		CHANGED: Recipients passed as gpgme_key_t[].
 gpgme_op_encrypt_sign		CHANGED: Recipients passed as gpgme_key_t[].
 gpgme_op_encrypt_sign_start	CHANGED: Recipients passed as gpgme_key_t[].
 gpgme_op_export_start		CHANGED: User IDs passed as patterns.
 gpgme_op_export			CHANGED: User IDs passed as patterns.
 gpgme_op_export_ext_start	NEW
 gpgme_op_export_ext		NEW
 gpgme_keylist_mode_t		NEW
 gpgme_sigsum_t			NEW
 gpgme_engine_info_t		NEW
 gpgme_get_engine_info		CHANGED: Return info structure instead XML.
 gpgme_get_protocol_name		NEW
 gpgme_cancel			REMOVED: Return error in callback directly.
 gpgme_op_genkey			CHANGED: FPR argument dropped.
 gpgme_op_genkey_result		NEW
 gpgme_genkey_result_t		NEW
 gpgme_op_import_ext		DEPRECATED: Use gpgme_op_import_result.
 gpgme_op_import_result		NEW
 gpgme_import_status_t		NEW
 gpgme_import_result_t		NEW
 gpgme_pubkey_algo_t		NEW
 gpgme_hash_algo_t		NEW
 gpgme_invalid_key_t		NEW
 gpgme_new_signature_t		NEW
 gpgme_sign_result_t		NEW
 gpgme_op_sign_result		NEW
 gpgme_pubkey_algo_name		NEW
 gpgme_hash_algo_name		NEW
 gpgme_encrypt_result_t		NEW
 gpgme_op_encrypt_result		NEW
 gpgme_decrypt_result_t		NEW
 gpgme_op_decrypt_result		NEW
 gpgme_verify_result_t		NEW
 gpgme_op_verify_result		NEW
 gpgme_get_notation		REMOVED: Access verify result directly instead.
 gpgme_get_sig_key		DEPRECATED: Use gpgme_get_key with fingerprint.
 gpgme_get_sig_ulong_attr	DEPRECATED: Use verify result directly.
 gpgme_get_sig_string_attr	DEPRECATED: Use verify result directly.
 GPGME_SIG_STAT_*		DEPRECATED: Use error value in sig status.
 gpgme_get_sig_status		DEPRECATED: Use verify result directly.
 gpgme_trust_item_t		CHANGED: Now has user accessible data members.
 gpgme_trust_item_ref		NEW
 gpgme_trust_item_unref		NEW
 gpgme_trust_item_release	DEPRECATED: Use gpgme_trust_item_unref.
 gpgme_trust_item_get_string_attr DEPRECATED
 gpgme_trust_item_get_ulong_attr	DEPRECATED
 gpgme_get_key			CHANGED: Removed force_update argument.
 gpgme_subkey_t			NEW
 gpgme_key_sig_t			NEW
 gpgme_user_id_t			NEW
 gpgme_key_t			CHANGED: Now has user accessible data members.
 gpgme_key_get_string_attr	DEPRECATED
 gpgme_key_get_ulong_attr	DEPRECATED
 gpgme_key_sig_get_string_attr	DEPRECATED
 gpgme_key_sig_get_ulong_attr	DEPRECATED
 gpgme_key_get_as_xml		REMOVED
 gpgme_key_list_result_t		NEW
 gpgme_op_keylist_result		NEW
 gpgme_get_op_info		REMOVED
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.4.0 (2002-12-23)
 ------------------------------------------------
 
  * Key generation returns the fingerprint of the generated key.
 
  * New convenience function gpgme_get_key.
 
  * Supports signatures of user IDs in keys via the new
    GPGME_KEYLIST_MODE_SIGS keylist mode and the
    gpgme_key_sig_get_string_attr and gpgme_key_sig_get_ulong_attr
    interfaces.  The XML info about a key also includes the signatures
    if available.
 
  * New data object interface, which is more flexible and transparent.
 
  * Interface changes relative to the 0.3.9 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 GpgmeDataReadCb			NEW
 GpgmeDataWriteCb		NEW
 GpgmeDataSeekCb			NEW
 GpgmeDataReleaseCb		NEW
 GpgmeDataCbs			NEW
 gpgme_data_read			CHANGED: Match read() closely.
 gpgme_data_write		CHANGED: Match write() closely.
 gpgme_data_seek			NEW
 gpgme_data_new_from_fd		NEW
 gpgme_data_new_from_stream	NEW
 gpgme_data_new_from_cbs		NEW
 gpgme_data_rewind		DEPRECATED: Replaced by gpgme_data_seek().
 gpgme_data_new_from_read_cb	DEPRECATED: Replaced by gpgme_data_from_cbs().
 gpgme_data_get_type		REMOVED: No replacement.
 gpgme_op_verify			CHANGED: Take different data objects for
 				signed text and plain text.
 gpgme_op_verify_start		CHANGED: See gpgme_op_verify.
 gpgme_check_engine		REMOVED: Deprecated since 0.3.0.
 gpgme_op_genkey			CHANGED: New parameter FPR.
 GPGME_KEYLIST_MODE_SIGS		NEW
 gpgme_key_sig_get_string_attr	NEW
 gpgme_key_sig_get_ulong_attr	NEW
 gpgme_get_key			NEW
 GPGME_ATTR_SIG_CLASS		NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.16 (2003-11-19)
 -------------------------------------------------
 
  * Compatibility fixes for GnuPG 1.9.x
 
 Noteworthy changes in version 0.3.15 (2003-02-18)
 -------------------------------------------------
 
  * The progress status is sent via the progress callbacks in
    gpgme_op_edit.
 
  * Bug fix for signing operations with explicit signer settings for
    the CMS protocol.
 
 Noteworthy changes in version 0.3.14 (2002-12-04)
 -------------------------------------------------
 
  * GPGME-Plug is now in its own package "cryptplug".
 
  * Workaround for a setlocale problem.  Fixed a segv related to not
    correctly as closed marked file descriptors.
 
 Noteworthy changes in version 0.3.13 (2002-11-20)
 -------------------------------------------------
 
  * Release due to changes in gpgmeplug.
 
 Noteworthy changes in version 0.3.12 (2002-10-15)
 -------------------------------------------------
 
  * Fixed some bux with key listings.
 
  * The development has been branched to clean up some API issues.
    This 0.3 series will be kept for compatibility reasons; so do don't
    expect new features.
 
 Noteworthy changes in version 0.3.11 (2002-09-20)
 -------------------------------------------------
 
  * Bug fixes.
 
 Noteworthy changes in version 0.3.10 (2002-09-02)
 -------------------------------------------------
 
  * Setting the signing keys for the CMS protocol does now work.
 
  * The signers setting is honoured by gpgme_op_edit.
 
 Noteworthy changes in version 0.3.9 (2002-08-21)
 ------------------------------------------------
 
  * A spec file for creating RPMs has been added.
 
  * An experimental interface to GnuPG's --edit-key functionality is
    introduced, see gpgme_op_edit.
 
  * The new gpgme_import_ext function provides a convenient access to
    the number of processed keys.
 
  * Interface changes relative to the 0.3.8 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 GpgmeStatusCode			NEW
 GpgmeEditCb			NEW
 gpgme_op_edit_start		NEW
 gpgme_op_edit			NEW
 gpgme_op_import_ext		NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.8 (2002-06-25)
 ------------------------------------------------
 
  * It is possible to use an outside event loop for the I/O to the
    crypto engine by setting the I/O callbacks with gpgme_set_io_cbs.
 
  * Interface changes relative to the 0.3.6 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 GpgmeIOCb			NEW
 GpgmeRegisterIOCb		NEW
 GpgmeRemoveIOCb			NEW
 GpgmeEventIO			NEW
 GpgmeEventIOCb			NEW
 struct GpgmeIOCbs		NEW
 gpgme_set_io_cbs		NEW
 gpgme_get_io_cbs		NEW
 GPGME_ATTR_ERRTOK		NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.7 (2002-06-04)
 ------------------------------------------------
 
  * GPGME_ATTR_OTRUST is implemented now.
 
  * A first step toward thread safeness has been achieved, see the
    documentation for details.  Supported thread libraries are pthread
    and Pth.
 
 Noteworthy changes in version 0.3.6 (2002-05-03)
 ------------------------------------------------
 
  * All error output of the gpgsm backend is send to the bit bucket.
 
  * The signature verification functions are extended.  Instead of
    always returning GPGME_SIG_STATUS_GOOD, the functions new codes for
    expired signatures.  2 new functions may be used to retrieve more
    detailed information like the signature expiration time and a
    validity information of the key without an extra key looking.
 
  * The current passphrase callback and progress meter callback can be
    retrieved with the new functions gpgme_get_passphrase_cb and
    gpgme_get_progress_cb respectively.
 
  * Interface changes relative to the 0.3.5 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_get_passphrase_cb		NEW
 gpgme_get_progress_cb		NEW
 GpgmeDataEncoding               NEW
 gpgme_data_set_encoding         NEW
 gpgme_data_get_encoding         NEW
 GPGME_SIG_STAT_GOOD_EXP         NEW
 GPGME_SIG_STAT_GOOD_EXPKEY      NEW
 gpgme_op_verify                 CHANGED: Returns more status codes.
 GPGME_ATTR_SIG_STATUS           NEW
 gpgme_get_sig_string_attr       NEW
 gpgme_get_sig_ulong_attr        NEW
 gpgme_get_protocol              NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.5 (2002-04-01)
 ------------------------------------------------
 
  * gpgme_op_encrypt can be called with RECIPIENTS being 0.  In this
    case, symmetric encryption is performed.  Note that this requires a
    passphrase from the user.
 
  * More information is returned for X.509 certificates.
 
  * Interface changes relative to the 0.3.4 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_op_encrypt		EXTENDED: Symmetric encryption possible
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.4 (2002-03-04)
 ------------------------------------------------
 
  * gpgme_op_encrypt does now fail with GPGME_Invalid_Recipients if
    some recipients have been invalid, whereas earlier versions
    succeeded in this case.  The plaintext is still encrypted for all valid
    recipients, so the application might take this error as a hint that
    the ciphertext is not usable for all requested recipients.
    Information about invalid recipients is available with gpgme_get_op_info.
 
  * gpgme_op_verify now allows to pass an uninitialized data object as
    its plaintext argument to check for normal and cleartext
    signatures.  The plaintext is then returned in the data object.
 
  * New interfaces gpgme_set_include_certs and gpgme_get_include_certs
    to set and get the number of certifications to include in S/MIME
    signed messages.
 
  * New interfaces gpgme_op_encrypt_sign and gpgme_op_encrypt_sign_start
    to encrypt and sign a message in a combined operation.
 
  * New interface gpgme_op_keylist_ext_start to search for multiple patterns.
 
  * gpgme_key_get_ulong_attr supports the GPGME_ATTR_EXPIRE attribute.
 
  * Interface changes relative to the 0.3.3 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_op_encrypt		CHANGED: Can fail with GPGME_Invalid_Recipients
 gpgme_op_verify			EXTENDED: Accepts uninitialized text argument
 gpgme_key_get_ulong_attr	EXTENDED: Supports GPGME_ATTR_EXPIRE
 gpgme_set_include_certs		NEW
 gpgme_get_include_certs		NEW
 gpgme_op_encrypt_sign		NEW
 gpgme_op_encrypt_sign_start	NEW
 gpgme_op_keylist_ext_start	NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.3 (2002-02-12)
 ------------------------------------------------
 
  * Fix the Makefile in jnlib.
 
  * Fix the test suite (hopefully).  It should clean up all its state
    with `make check' now.
 
 
 Noteworthy changes in version 0.3.2 (2002-02-10)
 ------------------------------------------------
 
  * Remove erroneous dependency on libgcrypt in jnlib.
 
 
 Noteworthy changes in version 0.3.1 (2002-02-09)
 ------------------------------------------------
 
  * There is a Texinfo manual documenting the API.
 
  * The gpgme_set_keylist_mode function returns an error, and changed
    its meaning.  It is no longer usable to select between normal and
    fast mode (newer versions of GnuPG will always be fast), but
    selects between local keyring, remote keyserver, or both.
    For this, two new macros are defined, GPGME_KEYLIST_MODE_LOCAL
    and GPGME_KEYLIST_MODE_EXTERN.  To make it possible to modify the
    current setting, a function gpgme_get_keylist_mode was added to
    retrieve the current mode.
 
  * gpgme_wait accepts a new argument STATUS to return the error status
    of the operation on the context.  Its definition is closer to
    waitpid() now than before.
 
  * The LENGTH argument to gpgme_data_new_from_filepart changed its
    type from off_t to the unsigned size_t.
 
  * The R_HD argument to the GpgmePassphraseCb type changed its type
    from void* to void**.
 
  * New interface gpgme_op_trustlist_end() to match
    gpgme_op_keylist_end().
 
  * The CryptPlug modules have been renamed to gpgme-openpgp and
    gpgme-smime, and they are installed in pkglibdir by `make install'.
 
  * An idle function can be registered with gpgme_register_idle().
 
  * The GpgSM backend supports key generation with gpgme_op_genkey().
 
  * Interface changes relative to the 0.3.0 release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_data_new_from_filepart	CHANGED: Type of LENGTH is size_t.
 GpgmePassphraseCb               CHANGED: Type of R_HD is void **.
 gpgme_wait                      CHANGED: New argument STATUS.
 gpgme_set_keylist_mode          CHANGED: Type of return value is GpgmeError.
                                 The function has a new meaning!
 gpgme_get_keylist_mode          NEW
 GPGME_KEYLIST_MODE_LOCAL        NEW
 GPGME_KEYLIST_MODE_EXTERN       NEW
 gpgme_op_trustlist_next		NEW
 GpgmeIdleFunc                   NEW
 gpgme_register_idle             NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Noteworthy changes in version 0.3.0 (2001-12-19)
 ------------------------------------------------
 
  * New interface gpgme_set_protocol() to set the protocol and thus the
    crypto engine to be used by the context.  Currently, the OpenPGP
    and the CMS protocols are supported.  They are specified by the new
    preprocessor symbols GPGME_PROTOCOL_OpenPGP and GPGME_PROTOCOL_CMS.
    A new context uses the OpenPGP engine by default.
 
  * gpgme_get_engine_info() returns information for all crypto engines
    compiled into the library.  The XML format has changed.  To
    reliably get the version of a crypto engine, the <version> tag
    after the appropriate <protocol> tag has to be looked for.
 
  * New interface gpgme_engine_check_version(), obsoleting
    gpgme_check_engine().  Check the version of all engines you are
    supporting in your software.
 
  * GpgmeKey lists the user ids in the order as they are returned by
    GnuPG, first the primary key with index 0, then the sub-user ids.
 
  * New operation gpgme_op_decrypt_verify() to decrypt and verify
    signatures simultaneously.
 
  * The new interface gpgme_op_keylist_end() terminates a pending
    keylist operation.  A keylist operation is also terminated when
    gpgme_op_keylist_next() returns GPGME_EOF.
 
  * GPGME can be compiled without GnuPG being installed (`--with-gpg=PATH'),
    cross-compiled, or even compiled without support for GnuPG
    (`--without-gpg').
 
  * GPGME can be compiled with support for GpgSM (GnuPG for S/MIME,
    `--with-gpgsm=PATH').  It is enabled by default if the `gpgsm' is found
    in the path, but it can also be compiled without support for GpgSM
    (`--without-gpgsm').
 
  * CryptPlug modules for GPGME are included and can be enabled at
    configure time (`--enable-gpgmeplug').  There is one module which
    uses the GnuPG engine (`gpgmeplug') and one module which uses the
    GpgSM engine (`gpgsmplug').
 
  * Interface changes relative to the latest 0.2.x release:
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 gpgme_key_get_as_xml		CHANGED: Sub-user ids reversed in order.
 gpgme_key_get_string_attr	CHANGED: User ids reversed in order.
 gpgme_key_get_ulong_attr	CHANGED: User ids reversed in order.
 gpgme_get_engine_info		CHANGED: New format, extended content.
 gpgme_engine_check_version	NEW
 gpgme_decrypt_verify_start	NEW
 gpgme_decrypt_verify		NEW
 gpgme_op_keylist_next		NEW
 gpgme_set_protocol		NEW
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 
 Noteworthy changes in version 0.2.3 (2001-09-17)
 ------------------------------------------------
 
  * New function gpgme_get_op_info which can be used to get the micalg
    parameter needed for MOSS.
 
  * New functions gpgme_get_armor and gpgme_get_textmode.
 
  * The usual bug fixes and some minor functionality improvements.
 
  * Added a simple encryption component for MS-Windows; however the
    build procedure might have some problems.
 
 
 Noteworthy changes in version 0.2.2 (2001-06-12)
 ------------------------------------------------
 
  * Implemented a key cache.
 
  * Fixed a race condition under W32 and some other bug fixes.
 
 
 Noteworthy changes in version 0.2.1 (2001-04-02)
 ------------------------------------------------
 
  * Changed debug output and GPGME_DEBUG variable (gpgme/debug.c)
 
  * Handle GnuPG's new key capabilities output and support revocation
    et al. attributes
 
  * Made the W32 support more robust.
 
 
  Copyright 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009,
            2010 g10 Code GmbH
 
  This file is free software; as a special exception the author gives
  unlimited permission to copy and/or distribute it, with or without
  modifications, as long as this notice is preserved.
 
  This file is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
diff --git a/doc/gpgme.texi b/doc/gpgme.texi
index 11147862..ea6693ef 100644
--- a/doc/gpgme.texi
+++ b/doc/gpgme.texi
@@ -1,8347 +1,8358 @@
 \input texinfo                   @c -*- mode: texinfo; coding: utf-8; -*-
 @documentencoding UTF-8
 @setfilename gpgme.info
 @include defs.inc
 @settitle The `GnuPG Made Easy' Reference Manual
 
 @dircategory GNU Libraries
 @direntry
 * @acronym{GPGME}: (gpgme).          Adding support for cryptography to your program.
 @end direntry
 
 @c Unify some of the indices.
 @syncodeindex tp fn
 @syncodeindex pg fn
 
 @copying
 Copyright @copyright{} 2002--2008, 2010, 2012--2018 g10 Code GmbH.
 
 @quotation
 Permission is granted to copy, distribute and/or modify this document
 under the terms of the GNU General Public License as published by the
 Free Software Foundation; either version 3 of the License, or (at your
 option) any later version. The text of the license can be found in the
 section entitled ``Copying''.
 @end quotation
 
 This document is distributed in the hope that it will be useful, but
 WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 General Public License for more details.
 @end copying
 
 @c Macros used by the description of the UI server protocol
 @macro clnt{string}
   @sc{c:} \string\
 @end macro
 @macro srvr{string}
   @sc{s:} \string\
 @end macro
 
 @c API version.
 @macro since{string}
   @sc{Since:} \string\
 @end macro
 
 
 @c
 @c  T I T L E  P A G E
 @c
 @ifinfo
 This file documents the @acronym{GPGME} library.
 
 This is Edition @value{EDITION}, last updated @value{UPDATED}, of
 @cite{The `GnuPG Made Easy' Reference Manual}, for Version
 @value{VERSION}.
 
 @c NOTE: Don't forget to update the year for the TeX version, too.
 @insertcopying
 
 @end ifinfo
 
 @c We do not want that bastard short titlepage.
 @c @iftex
 @c @shorttitlepage The `GnuPG Made Easy' Reference Manual
 @c @end iftex
 @titlepage
 @center @titlefont{The `GnuPG Made Easy'}
 @sp 1
 @center @titlefont{Reference Manual}
 @sp 6
 @center Edition @value{EDITION}
 @sp 1
 @center last updated @value{UPDATED}
 @sp 1
 @center for version @value{VERSION}
 @page
 @vskip 0pt plus 1filll
 Published by The GnuPG Project@* c/o g10 Code GmbH@* Hüttenstr. 61@* 40699 Erkrath, Germany
 
 @insertcopying
 @end titlepage
 @page
 
 @summarycontents
 @contents
 
 @ifnottex
 @node Top
 @top Main Menu
 This is Edition @value{EDITION}, last updated @value{UPDATED}, of
 @cite{The `GnuPG Made Easy' Reference Manual}, for Version
 @value{VERSION} of the @acronym{GPGME} library.
 @end ifnottex
 
 @menu
 * Introduction::                  How to use this manual.
 * Preparation::                   What you should do before using the library.
 * Protocols and Engines::         Supported crypto protocols.
 * Algorithms::                    Supported algorithms.
 * Error Handling::                Error numbers and their meanings.
 * Exchanging Data::               Passing data to and from @acronym{GPGME}.
 * Contexts::                      Handling @acronym{GPGME} contexts.
 
 Appendices
 
 * UI Server Protocol::            The GnuPG UI Server Protocol.
 * Debugging::                     How to solve problems.
 * Deprecated Functions::          Documentation of deprecated functions.
 
 * Library Copying::               The GNU Lesser General Public License says
                                   how you can copy and share `GnuPG Made Easy'.
 * Copying::                       The GNU General Public License says how you
                                   can copy and share this manual.
 
 Indices
 
 * Concept Index::                 Index of concepts and programs.
 * Function and Data Index::       Index of functions, variables and data types.
 
 @detailmenu
  --- The Detailed Node Listing ---
 
 Introduction
 
 * Getting Started::               Purpose of the manual, and how to use it.
 * Features::                      Reasons to install and use @acronym{GPGME}.
 * Overview::                      Basic architecture of the @acronym{GPGME} library.
 
 Preparation
 
 * Header::                        What header file you need to include.
 * Building the Source::           Compiler options to be used.
 * Largefile Support (LFS)::       How to use @acronym{GPGME} with LFS.
 * Using Automake::                Compiler options to be used the easy way.
 * Using Libtool::                 Avoiding compiler options entirely.
 * Library Version Check::         Getting and verifying the library version.
 * Signal Handling::               How @acronym{GPGME} affects signal handling.
 * Multi-Threading::               How @acronym{GPGME} can be used in an MT environment.
 
 Protocols and Engines
 
 * Engine Version Check::          Verifying the engine version.
 * Engine Information::            Obtaining more information about the engines.
 * Engine Configuration::          Changing the engine configuration.
 * OpenPGP::                       Support for the OpenPGP protocol.
 * Cryptographic Message Syntax::  Support for the CMS.
 
 Algorithms
 
 * Public Key Algorithms::         A list of all public key algorithms.
 * Hash Algorithms::               A list of all hash algorithms.
 
 Error Handling
 
 * Error Values::                  The error value and what it means.
 * Error Codes::                   A list of important error codes.
 * Error Sources::                 A list of important error sources.
 * Error Strings::                 How to get a descriptive string from a value.
 
 Exchanging Data
 
 * Creating Data Buffers::         Creating new data buffers.
 * Destroying Data Buffers::       Releasing data buffers.
 * Manipulating Data Buffers::     Operations on data buffers.
 
 Creating Data Buffers
 
 * Memory Based Data Buffers::     Creating memory based data buffers.
 * File Based Data Buffers::       Creating file based data buffers.
 * Callback Based Data Buffers::   Creating callback based data buffers.
 
 Manipulating Data Buffers
 
 * Data Buffer I/O Operations::    I/O operations on data buffers.
 * Data Buffer Meta-Data::         Meta-data manipulation of data buffers.
 * Data Buffer Convenience::       Convenience function for data buffers.
 
 Contexts
 
 * Creating Contexts::             Creating new @acronym{GPGME} contexts.
 * Destroying Contexts::           Releasing @acronym{GPGME} contexts.
 * Result Management::             Managing the result of crypto operations.
 * Context Attributes::            Setting properties of a context.
 * Key Management::                Managing keys with @acronym{GPGME}.
 * Crypto Operations::             Using a context for cryptography.
 * Miscellaneous::                 Miscellaneous operations.
 * Run Control::                   Controlling how operations are run.
 
 Context Attributes
 
 * Protocol Selection::            Selecting the protocol used by a context.
 * Crypto Engine::                 Configuring the crypto engine.
 * Setting the Sender::            How to tell the engine the sender.
 * ASCII Armor::                   Requesting @acronym{ASCII} armored output.
 * Text Mode::                     Choosing canonical text mode.
 * Offline Mode::                  Choosing offline mode.
 * Included Certificates::         Including a number of certificates.
 * Key Listing Mode::              Selecting key listing mode.
 * Passphrase Callback::           Getting the passphrase from the user.
 * Progress Meter Callback::       Being informed about the progress.
 * Status Message Callback::       Status messages received from gpg.
 * Locale::                        Setting the locale of a context.
 
 Key Management
 
 * Key objects::                   Description of the key structures.
 * Listing Keys::                  Browsing the list of available keys.
 * Information About Keys::        Requesting detailed information about keys.
 * Manipulating Keys::             Operations on keys.
 * Generating Keys::               Creating new key pairs.
 * Signing Keys::                  Adding key signatures to public keys.
 * Exporting Keys::                Retrieving key data from the key ring.
 * Importing Keys::                Adding keys to the key ring.
 * Deleting Keys::                 Removing keys from the key ring.
 * Changing Passphrases::          Change the passphrase of a key.
 * Changing TOFU Data::            Changing data pertaining to TOFU.
 * Advanced Key Editing::          Advanced key edit operation.
 
 Crypto Operations
 
 * Decrypt::                       Decrypting a ciphertext.
 * Verify::                        Verifying a signature.
 * Decrypt and Verify::            Decrypting a signed ciphertext.
 * Sign::                          Creating a signature.
 * Encrypt::                       Encrypting a plaintext.
 
 Sign
 
 * Selecting Signers::             How to choose the keys to sign with.
 * Creating a Signature::          How to create a signature.
 * Signature Notation Data::       How to add notation data to a signature.
 
 Encrypt
 
 * Encrypting a Plaintext::        How to encrypt a plaintext.
 
 Miscellaneous
 
 * Running other Programs::        Running other Programs.
 * Using the Assuan protocol::     Using the Assuan protocol.
 * Checking for updates::          How to check for software updates.
 
 Run Control
 
 * Waiting For Completion::        Waiting until an operation is completed.
 * Using External Event Loops::    Advanced control over what happens when.
 * Cancellation::                  How to end pending operations prematurely.
 
 Using External Event Loops
 
 * I/O Callback Interface::        How I/O callbacks are registered.
 * Registering I/O Callbacks::     How to use I/O callbacks for a context.
 * I/O Callback Example::          An example how to use I/O callbacks.
 * I/O Callback Example GTK+::     How to integrate @acronym{GPGME} in GTK+.
 * I/O Callback Example GDK::      How to integrate @acronym{GPGME} in GDK.
 * I/O Callback Example Qt::       How to integrate @acronym{GPGME} in Qt.
 
 @end detailmenu
 @end menu
 
 @node Introduction
 @chapter Introduction
 
 `GnuPG Made Easy' (@acronym{GPGME}) is a C language library that
 allows to add support for cryptography to a program.  It is designed
 to make access to public key crypto engines like GnuPG or GpgSM easier
 for applications.  @acronym{GPGME} provides a high-level crypto API
 for encryption, decryption, signing, signature verification and key
 management.
 
 @acronym{GPGME} uses GnuPG and GpgSM as its backends to support
 OpenPGP and the Cryptographic Message Syntax (CMS).
 
 @menu
 * Getting Started::               Purpose of the manual, and how to use it.
 * Features::                      Reasons to install and use @acronym{GPGME}.
 * Overview::                      Basic architecture of the @acronym{GPGME} library.
 @end menu
 
 
 @node Getting Started
 @section Getting Started
 
 This manual documents the @acronym{GPGME} library programming
 interface.  All functions and data types provided by the library are
 explained.
 
 The reader is assumed to possess basic knowledge about cryptography in
 general, and public key cryptography in particular.  The underlying
 cryptographic engines that are used by the library are not explained,
 but where necessary, special features or requirements by an engine are
 mentioned as far as they are relevant to @acronym{GPGME} or its users.
 
 This manual can be used in several ways.  If read from the beginning
 to the end, it gives a good introduction into the library and how it
 can be used in an application.  Forward references are included where
 necessary.  Later on, the manual can be used as a reference manual to
 get just the information needed about any particular interface of the
 library.  Experienced programmers might want to start looking at the
 examples at the end of the manual, and then only read up those parts
 of the interface which are unclear.
 
 The documentation for the language bindings is currently not included
 in this manual.  Those languages bindings follow the general
 programming model of @acronym{GPGME} but may provide some extra high
 level abstraction on top of the @acronym{GPGME} style API.  For now
 please see the README files in the @file{lang/} directory of the
 source distribution.
 
 
 @node Features
 @section Features
 
 @acronym{GPGME} has a couple of advantages over other libraries doing
 a similar job, and over implementing support for GnuPG or other crypto
 engines into your application directly.
 
 @table @asis
 @item it's free software
 Anybody can use, modify, and redistribute it under the terms of the GNU
 Lesser General Public License (@pxref{Library Copying}).
 
 @item it's flexible
 @acronym{GPGME} provides transparent support for several cryptographic
 protocols by different engines.  Currently, @acronym{GPGME} supports
 the OpenPGP protocol using GnuPG as the backend, and the Cryptographic
 Message Syntax using GpgSM as the backend.
 
 @item it's easy
 @acronym{GPGME} hides the differences between the protocols and
 engines from the programmer behind an easy-to-use interface.  This way
 the programmer can focus on the other parts of the program, and still
 integrate strong cryptography in his application.  Once support for
 @acronym{GPGME} has been added to a program, it is easy to add support
 for other crypto protocols once @acronym{GPGME} backends provide them.
 
 @item it's language friendly
 @acronym{GPGME} comes with languages bindings for several common
 programming languages: Common Lisp, C++, Python 2, and Python 3.
 @end table
 
 @node Overview
 @section Overview
 
 @acronym{GPGME} provides a data abstraction that is used to pass data
 to the crypto engine, and receive returned data from it.  Data can be
 read from memory or from files, but it can also be provided by a
 callback function.
 
 The actual cryptographic operations are always set within a context.
 A context provides configuration parameters that define the behaviour
 of all operations performed within it.  Only one operation per context
 is allowed at any time, but when one operation is finished, you can
 run the next operation in the same context.  There can be more than
 one context, and all can run different operations at the same time.
 
 Furthermore, @acronym{GPGME} has rich key management facilities
 including listing keys, querying their attributes, generating,
 importing, exporting and deleting keys, and acquiring information
 about the trust path.
 
 With some precautions, @acronym{GPGME} can be used in a multi-threaded
 environment, although it is not completely thread safe and thus needs
 the support of the application.
 
 
 @node Preparation
 @chapter Preparation
 
 To use @acronym{GPGME}, you have to perform some changes to your
 sources and the build system.  The necessary changes are small and
 explained in the following sections.  At the end of this chapter, it
 is described how the library is initialized, and how the requirements
 of the library are verified.
 
 @menu
 * Header::                        What header file you need to include.
 * Building the Source::           Compiler options to be used.
 * Largefile Support (LFS)::       How to use @acronym{GPGME} with LFS.
 * Using Automake::                Compiler options to be used the easy way.
 * Using Libtool::                 Avoiding compiler options entirely.
 * Library Version Check::         Getting and verifying the library version.
 * Signal Handling::               How @acronym{GPGME} affects signal handling.
 * Multi-Threading::               How @acronym{GPGME} can be used in an MT environment.
 @end menu
 
 
 @node Header
 @section Header
 @cindex header file
 @cindex include file
 
 All interfaces (data types and functions) of the library are defined
 in the header file `gpgme.h'.  You must include this in all programs
 using the library, either directly or through some other header file,
 like this:
 
 @example
 #include <gpgme.h>
 @end example
 
 The name space of @acronym{GPGME} is @code{gpgme_*} for function names
 and data types and @code{GPGME_*} for other symbols.  Symbols internal
 to @acronym{GPGME} take the form @code{_gpgme_*} and @code{_GPGME_*}.
 
 Because @acronym{GPGME} makes use of the GPG Error library, using
 @acronym{GPGME} will also use the @code{GPG_ERR_*} name space
 directly, and the @code{gpg_err*}, @code{gpg_str*}, and @code{gpgrt_*}
 name space indirectly.
 
 
 @node Building the Source
 @section Building the Source
 @cindex compiler options
 @cindex compiler flags
 
 If you want to compile a source file including the `gpgme.h' header
 file, you must make sure that the compiler can find it in the
 directory hierarchy.  This is accomplished by adding the path to the
 directory in which the header file is located to the compilers include
 file search path (via the @option{-I} option).
 
 However, the path to the include file is determined at the time the
 source is configured.  To solve this problem, gpgme ships with a small
 helper program @command{gpgme-config} that knows about the path to the
 include file and other configuration options.  The options that need
 to be added to the compiler invocation at compile time are output by
 the @option{--cflags} option to @command{gpgme-config}.  The following
 example shows how it can be used at the command line:
 
 @example
 gcc -c foo.c `gpgme-config --cflags`
 @end example
 
 Adding the output of @samp{gpgme-config --cflags} to the compiler
 command line will ensure that the compiler can find the
 @acronym{GPGME} header file.
 
 A similar problem occurs when linking the program with the library.
 Again, the compiler has to find the library files.  For this to work,
 the path to the library files has to be added to the library search
 path (via the @option{-L} option).  For this, the option
 @option{--libs} to @command{gpgme-config} can be used.  For
 convenience, this option also outputs all other options that are
 required to link the program with @acronym{GPGME} (in particular, the
 @samp{-lgpgme} option).  The example shows how to link @file{foo.o}
 with the @acronym{GPGME} library to a program @command{foo}.
 
 @example
 gcc -o foo foo.o `gpgme-config --libs`
 @end example
 
 Of course you can also combine both examples to a single command by
 specifying both options to @command{gpgme-config}:
 
 @example
 gcc -o foo foo.c `gpgme-config --cflags --libs`
 @end example
 
 If you need to detect the installed language bindings you can use list
 them using:
 
 @example
 gpgme-config --print-lang
 @end example
 
 or test for the availability using
 
 @example
 gpgme-config --have-lang=python && echo 'Bindings for Pythons available'
 @end example
 
 
 @node Largefile Support (LFS)
 @section Largefile Support (LFS)
 @cindex largefile support
 @cindex LFS
 
 @acronym{GPGME} is compiled with largefile support by default, if it
 is available on the system.  This means that GPGME supports files
 larger than two gigabyte in size, if the underlying operating system
 can.  On some systems, largefile support is already the default.  On
 such systems, nothing special is required.  However, some systems
 provide only support for files up to two gigabyte in size by default.
 Support for larger file sizes has to be specifically enabled.
 
 To make a difficult situation even more complex, such systems provide
 two different types of largefile support.  You can either get all
 relevant functions replaced with alternatives that are largefile
 capable, or you can get new functions and data types for largefile
 support added.  Those new functions have the same name as their
 smallfile counterparts, but with a suffix of 64.
 
 An example: The data type @code{off_t} is 32 bit wide on GNU/Linux PC
 systems.  To address offsets in large files, you can either enable
 largefile support add-on.  Then a new data type @code{off64_t} is
 provided, which is 64 bit wide.  Or you can replace the existing
 @code{off_t} data type with its 64 bit wide counterpart.  All
 occurrences of @code{off_t} are then automagically replaced.
 
 As if matters were not complex enough, there are also two different
 types of file descriptors in such systems.  This is important because
 if file descriptors are exchanged between programs that use a
 different maximum file size, certain errors must be produced on some
 file descriptors to prevent subtle overflow bugs from occurring.
 
 As you can see, supporting two different maximum file sizes at the
 same time is not at all an easy task.  However, the maximum file size
 does matter for @acronym{GPGME}, because some data types it uses in
 its interfaces are affected by that.  For example, the @code{off_t}
 data type is used in the @code{gpgme_data_seek} function, to match its
 @acronym{POSIX} counterpart.  This affects the call-frame of the
 function, and thus the ABI of the library.  Furthermore, file
 descriptors can be exchanged between GPGME and the application.
 
 For you as the user of the library, this means that your program must
 be compiled in the same file size mode as the library.  Luckily, there
 is absolutely no valid reason for new programs to not enable largefile
 support by default and just use that.  The compatibility modes (small
 file sizes or dual mode) can be considered an historic artefact, only
 useful to allow for a transitional period.
 
 On POSIX platforms @acronym{GPGME} is compiled using largefile support
 by default.  This means that your application must do the same, at
 least as far as it is relevant for using the @file{gpgme.h} header
 file.  All types in this header files refer to their largefile
 counterparts, if they are different from any default types on the
 system.
 
 On 32 and 64 bit Windows platforms @code{off_t} is declared as 32 bit
 signed integer.  There is no specific support for LFS in the C
 library.  The recommendation from Microsoft is to use the native
 interface (@code{CreateFile} et al.) for large files.  Released binary
 versions of @acronym{GPGME} (libgpgme-11.dll) have always been build
 with a 32 bit @code{off_t}.  To avoid an ABI break we stick to this
 convention for 32 bit Windows by using @code{long} there.
 @acronym{GPGME} versions for 64 bit Windows have never been released
 and thus we are able to use @code{int64_t} instead of @code{off_t}
 there.  For easier migration the typedef @code{gpgme_off_t} has been
 defined.  The reason we cannot use @code{off_t} directly is that some
 toolchains (e.g. mingw64) introduce a POSIX compatible hack for
 @code{off_t}.  Some widely used toolkits make use of this hack and in
 turn @acronym{GPGME} would need to use it also.  However, this would
 introduce an ABI break and existing software making use of libgpgme
 might suffer from a severe break.  Thus with version 1.4.2 we
 redefined all functions using @code{off_t} to use @code{gpgme_off_t}
 which is defined as explained above.  This way we keep the ABI well
 defined and independent of any toolchain hacks.  The bottom line is
 that LFS support in @acronym{GPGME} is only available on 64 bit
 versions of Windows.
 
 On POSIX platforms you can enable largefile support, if it is
 different from the default on the system the application is compiled
 on, by using the Autoconf macro @code{AC_SYS_LARGEFILE}.  If you do
 this, then you don't need to worry about anything else: It will just
 work.  In this case you might also want to use @code{AC_FUNC_FSEEKO}
 to take advantage of some new interfaces, and @code{AC_TYPE_OFF_T}
 (just in case).
 
 If you do not use Autoconf, you can define the preprocessor symbol
 @code{_FILE_OFFSET_BITS} to 64 @emph{before} including any header
 files, for example by specifying the option
 @code{-D_FILE_OFFSET_BITS=64} on the compiler command line.  You will
 also want to define the preprocessor symbol @code{LARGEFILE_SOURCE} to
 1 in this case, to take advantage of some new interfaces.
 
 If you do not want to do either of the above, you probably know enough
 about the issue to invent your own solution.  Just keep in mind that
 the @acronym{GPGME} header file expects that largefile support is
 enabled, if it is available.  In particular, we do not support dual
 mode (@code{_LARGEFILE64_SOURCE}).
 
 
 @node Using Automake
 @section Using Automake
 @cindex automake
 @cindex autoconf
 
 It is much easier if you use GNU Automake instead of writing your own
 Makefiles.  If you do that you do not have to worry about finding and
 invoking the @command{gpgme-config} script at all.  @acronym{GPGME}
 provides an extension to Automake that does all the work for you.
 
 @c A simple macro for optional variables.
 @macro ovar{varname}
 @r{[}@var{\varname\}@r{]}
 @end macro
 @defmac AM_PATH_GPGME (@ovar{minimum-version}, @ovar{action-if-found}, @ovar{action-if-not-found})
 @defmacx AM_PATH_GPGME_PTH (@ovar{minimum-version}, @ovar{action-if-found}, @ovar{action-if-not-found})
 @defmacx AM_PATH_GPGME_PTHREAD (@ovar{minimum-version}, @ovar{action-if-found}, @ovar{action-if-not-found})
 Check whether @acronym{GPGME} (at least version @var{minimum-version},
 if given) exists on the host system.  If it is found, execute
 @var{action-if-found}, otherwise do @var{action-if-not-found}, if
 given.
 
 Additionally, the function defines @code{GPGME_CFLAGS} to the flags
 needed for compilation of the program to find the @file{gpgme.h}
 header file, and @code{GPGME_LIBS} to the linker flags needed to link
 the program to the @acronym{GPGME} library.  If the used helper script
 does not match the target type you are building for a warning is
 printed and the string @code{libgcrypt} is appended to the variable
 @code{gpg_config_script_warn}.
 
 @code{AM_PATH_GPGME_PTH} checks for the version of @acronym{GPGME}
 that can be used with GNU Pth, and defines @code{GPGME_PTH_CFLAGS} and
 @code{GPGME_PTH_LIBS}.
 
 @code{AM_PATH_GPGME_PTHREAD} checks for the version of @acronym{GPGME}
 that can be used with the native pthread implementation, and defines
 @code{GPGME_PTHREAD_CFLAGS} and @code{GPGME_PTHREAD_LIBS}. Since
 version 1.8.0 this is no longer required to GPGME_PTHREAD as
 @acronym{GPGME} itself is thread safe.
 
 This macro searches for @command{gpgme-config} along the PATH.  If
 you are cross-compiling, it is useful to set the environment variable
 @code{SYSROOT} to the top directory of your target.  The macro will
 then first look for the helper program in the @file{bin} directory
 below that top directory.  An absolute directory name must be used for
 @code{SYSROOT}.  Finally, if the configure command line option
 @code{--with-gpgme-prefix} is used, only its value is used for the top
 directory below which the helper script is expected.
 
 @end defmac
 
 You can use the defined Autoconf variables like this in your
 @file{Makefile.am}:
 
 @example
 AM_CPPFLAGS = $(GPGME_CFLAGS)
 LDADD = $(GPGME_LIBS)
 @end example
 
 
 @node Using Libtool
 @section Using Libtool
 @cindex libtool
 
 The easiest way is to just use GNU Libtool.  If you use libtool, and
 link to @code{libgpgme.la}, @code{libgpgme-pth.la} or
 @code{libgpgme-pthread.la} respectively, everything will be done
 automatically by Libtool.
 
 
 @node Library Version Check
 @section Library Version Check
 @cindex version check, of the library
 
 @deftypefun {const char *} gpgme_check_version (@w{const char *@var{required_version}})
 The function @code{gpgme_check_version} has four purposes.  It can be
 used to retrieve the version number of the library.  In addition it
 can verify that the version number is higher than a certain required
 version number.  In either case, the function initializes some
 sub-systems, and for this reason alone it must be invoked early in
 your program, before you make use of the other functions in
 @acronym{GPGME}.  The last purpose is to run selftests.
 
 As a side effect for W32 based systems, the socket layer will get
 initialized.
 
 
 If @var{required_version} is @code{NULL}, the function returns a
 pointer to a statically allocated string containing the version number
 of the library.
 
 If @var{required_version} is not @code{NULL}, it should point to a
 string containing a version number, and the function checks that the
 version of the library is at least as high as the version number
 provided.  In this case, the function returns a pointer to a
 statically allocated string containing the version number of the
 library.  If @var{REQUIRED_VERSION} is not a valid version number, or
 if the version requirement is not met, the function returns
 @code{NULL}.
 
 If you use a version of a library that is backwards compatible with
 older releases, but contains additional interfaces which your program
 uses, this function provides a run-time check if the necessary
 features are provided by the installed version of the library.
 
 If a selftest fails, the function may still succeed.  Selftest errors
 are returned later when invoking @code{gpgme_new} or
 @code{gpgme-data_new}, so that a detailed error code can be returned
 (historically, @code{gpgme_check_version} does not return a detailed
 error code).
 @end deftypefun
 
 
 @deftypefun {int} gpgme_set_global_flag  @
             (@w{const char *@var{name}}, @
             @w{const char *@var{value}})
 
 @since{1.4.0}
 
 On some systems it is not easy to set environment variables and thus
 hard to use @acronym{GPGME}'s internal trace facility for debugging.
 This function has been introduced as an alternative way to enable
 debugging and for a couple of other rarely used tweaks.  It is
 important to assure that only one thread accesses @acronym{GPGME}
 functions between a call to this function and after the return from
 the call to @code{gpgme_check_version}.
 
 All currently supported features require that this function is called
 as early as possible --- even before @code{gpgme_check_version}.  The
 features are identified by the following values for @var{name}:
 
 @table @code
 @item debug
 To enable debugging use the string ``debug'' for @var{name} and
 @var{value} identical to the value used with the environment variable
 @code{GPGME_DEBUG}.
 
 @item disable-gpgconf
 Using this feature with any @var{value} disables the detection of the
 gpgconf program and thus forces GPGME to fallback into the simple
 OpenPGP only mode.  It may be used to force the use of GnuPG-1 on
 systems which have both GPG versions installed.  Note that in general
 the use of @code{gpgme_set_engine_info} is a better way to select a
 specific engine version.
 
 @item gpgconf-name
 @itemx gpg-name
 Set the name of the gpgconf respective gpg binary.  The defaults are
 @code{GNU/GnuPG/gpgconf} and @code{GNU/GnuPG/gpg}.  Under Unix the
 leading directory part is ignored.  Under Windows the leading
 directory part is used as the default installation directory; the
 @code{.exe} suffix is added by GPGME.  Use forward slashed even under
 Windows.
 
 @item require-gnupg
 Set the minimum version of the required GnuPG engine.  If that version
 is not met, GPGME fails early instead of trying to use the existent
 version.  The given version must be a string with major, minor, and
 micro number.  Example: "2.1.0".
 
 @item w32-inst-dir
 On Windows GPGME needs to know its installation directory to find its
 spawn helper.  This is in general no problem because a DLL has this
 information.  Some applications however link statically to GPGME and
 thus GPGME can only figure out the installation directory of this
 application which may be wrong in certain cases.  By supplying an
 installation directory as value to this flag, GPGME will assume that
 that directory is the installation directory.  This flag has no effect
 on non-Windows platforms.
 
 @end table
 
 This function returns @code{0} on success.  In contrast to other
 functions the non-zero return value on failure does not convey any
 error code.  For setting ``debug'' the only possible error cause is an
 out of memory condition; which would exhibit itself later anyway.
 Thus the return value may be ignored.
 @end deftypefun
 
 
 After initializing @acronym{GPGME}, you should set the locale
 information to the locale required for your output terminal.  This
 locale information is needed for example for the curses and Gtk
 pinentry.  Here is an example of a complete initialization:
 
 @example
 #include <locale.h>
 #include <gpgme.h>
 
 void
 init_gpgme (void)
 @{
   /* Initialize the locale environment.  */
   setlocale (LC_ALL, "");
   gpgme_check_version (NULL);
   gpgme_set_locale (NULL, LC_CTYPE, setlocale (LC_CTYPE, NULL));
 #ifdef LC_MESSAGES
   gpgme_set_locale (NULL, LC_MESSAGES, setlocale (LC_MESSAGES, NULL));
 #endif
 @}
 @end example
 
 Note that you are highly recommended to initialize the locale settings
 like this.  @acronym{GPGME} can not do this for you because it would
 not be thread safe.  The conditional on LC_MESSAGES is only necessary
 for portability to W32 systems.
 
 
 @node Signal Handling
 @section Signal Handling
 @cindex signals
 @cindex signal handling
 
 The @acronym{GPGME} library communicates with child processes (the
 crypto engines).  If a child process dies unexpectedly, for example
 due to a bug, or system problem, a @code{SIGPIPE} signal will be
 delivered to the application.  The default action is to abort the
 program.  To protect against this, @code{gpgme_check_version} sets the
 @code{SIGPIPE} signal action to @code{SIG_IGN}, which means that the
 signal will be ignored.
 
 @acronym{GPGME} will only do that if the signal action for
 @code{SIGPIPE} is @code{SIG_DEF} at the time
 @code{gpgme_check_version} is called.  If it is something different,
 @code{GPGME} will take no action.
 
 This means that if your application does not install any signal
 handler for @code{SIGPIPE}, you don't need to take any precautions.
 If you do install a signal handler for @code{SIGPIPE}, you must be
 prepared to handle any @code{SIGPIPE} events that occur due to
 @acronym{GPGME} writing to a defunct pipe.  Furthermore, if your
 application is multi-threaded, and you install a signal action for
 @code{SIGPIPE}, you must make sure you do this either before
 @code{gpgme_check_version} is called or afterwards.
 
 
 @node Multi-Threading
 @section Multi-Threading
 @cindex thread-safeness
 @cindex multi-threading
 
 The @acronym{GPGME} library is mostly thread-safe, and can be used
 in a multi-threaded environment but there are some requirements
 for multi-threaded use:
 
 @itemize @bullet
 @item
 The function @code{gpgme_check_version} must be called before any
 other function in the library, because it initializes the thread
 support subsystem in @acronym{GPGME}.  To achieve this in
 multi-threaded programs, you must synchronize the memory with respect
 to other threads that also want to use @acronym{GPGME}.  For this, it
 is sufficient to call @code{gpgme_check_version} before creating the
 other threads using @acronym{GPGME}@footnote{At least this is true for
 POSIX threads, as @code{pthread_create} is a function that
 synchronizes memory with respects to other threads.  There are many
 functions which have this property, a complete list can be found in
 POSIX, IEEE Std 1003.1-2003, Base Definitions, Issue 6, in the
 definition of the term ``Memory Synchronization''.  For other thread
 packages other, more relaxed or more strict rules may apply.}.
 
 @item
 Any @code{gpgme_data_t} and @code{gpgme_ctx_t} object must only be
 accessed by one thread at a time.  If multiple threads want to deal
 with the same object, the caller has to make sure that operations on
 that object are fully synchronized.
 
 @item
 Only one thread at any time is allowed to call @code{gpgme_wait}.  If
 multiple threads call this function, the caller must make sure that
 all invocations are fully synchronized.  It is safe to start
 asynchronous operations while a thread is running in gpgme_wait.
 
 @item
 The function @code{gpgme_strerror} is not thread safe.  You have to
 use @code{gpgme_strerror_r} instead.
 @end itemize
 
 
 @node Protocols and Engines
 @chapter Protocols and Engines
 @cindex protocol
 @cindex engine
 @cindex crypto engine
 @cindex backend
 @cindex crypto backend
 
 @acronym{GPGME} supports several cryptographic protocols, however, it
 does not implement them.  Rather it uses backends (also called
 engines) which implement the protocol.  @acronym{GPGME} uses
 inter-process communication to pass data back and forth between the
 application and the backend, but the details of the communication
 protocol and invocation of the backend is completely hidden by the
 interface.  All complexity is handled by @acronym{GPGME}.  Where an
 exchange of information between the application and the backend is
 necessary, @acronym{GPGME} provides the necessary callback function
 hooks and further interfaces.
 
 @deftp {Data type} {enum gpgme_protocol_t}
 @tindex gpgme_protocol_t
 The @code{gpgme_protocol_t} type specifies the set of possible protocol
 values that are supported by @acronym{GPGME}.  The following protocols
 are supported:
 
 @table @code
 @item GPGME_PROTOCOL_OpenPGP
 @itemx GPGME_PROTOCOL_OPENPGP
 This specifies the OpenPGP protocol.
 
 @item GPGME_PROTOCOL_CMS
 This specifies the Cryptographic Message Syntax.
 
 @item GPGME_PROTOCOL_GPGCONF
 Under development.  Please ask on @email{gnupg-devel@@gnupg.org} for help.
 
 @item GPGME_PROTOCOL_ASSUAN
 @since{1.2.0}
 
 This specifies the raw Assuan protocol.
 
 @item GPGME_PROTOCOL_G13
 @since{1.3.0}
 
 Under development.  Please ask on @email{gnupg-devel@@gnupg.org} for help.
 
 @item GPGME_PROTOCOL_UISERVER
 Under development.  Please ask on @email{gnupg-devel@@gnupg.org} for help.
 
 @item GPGME_PROTOCOL_SPAWN
 @since{1.5.0}
 
 Special protocol for use with @code{gpgme_op_spawn}.
 
 @item GPGME_PROTOCOL_UNKNOWN
 Reserved for future extension.  You may use this to indicate that the
 used protocol is not known to the application.  Currently,
 @acronym{GPGME} does not accept this value in any operation, though,
 except for @code{gpgme_get_protocol_name}.
 @end table
 @end deftp
 
 
 @deftypefun {const char *} gpgme_get_protocol_name (@w{gpgme_protocol_t @var{protocol}})
 The function @code{gpgme_get_protocol_name} returns a statically
 allocated string describing the protocol @var{protocol}, or
 @code{NULL} if the protocol number is not valid.
 @end deftypefun
 
 @menu
 * Engine Version Check::          Verifying the engine version.
 * Engine Information::            Obtaining more information about the engines.
 * Engine Configuration::          Changing the engine configuration.
 * OpenPGP::                       Support for the OpenPGP protocol.
 * Cryptographic Message Syntax::  Support for the CMS.
 * Assuan::                        Support for the raw Assuan protocol.
 @end menu
 
 
 @node Engine Version Check
 @section Engine Version Check
 @cindex version check, of the engines
 
 @deftypefun @w{const char *} gpgme_get_dirinfo (@w{cons char *@var{what}})
 @since{1.5.0}
 
 The function @code{gpgme_get_dirinfo} returns a statically allocated
 string with the value associated to @var{what}.  The returned values
 are the defaults and won't change even after
 @code{gpgme_set_engine_info} has been used to configure a different
 engine.  @code{NULL} is returned if no value is available.  Commonly
 supported values for @var{what} are:
 
 @table @code
 @item homedir
 Return the default home directory.
 
 @item sysconfdir
 Return the name of the system configuration directory
 
 @item bindir
 Return the name of the directory with GnuPG program files.
 
 @item libdir
 Return the name of the directory with GnuPG related library files.
 
 @item libexecdir
 Return the name of the directory with GnuPG helper program files.
 
 @item datadir
 Return the name of the directory with GnuPG shared data.
 
 @item localedir
 Return the name of the directory with GnuPG locale data.
 
 @item agent-socket
 Return the name of the socket to connect to the gpg-agent.
 
 @item agent-ssh-socket
 Return the name of the socket to connect to the ssh-agent component of
 gpg-agent.
 
 @item dirmngr-socket
 Return the name of the socket to connect to the dirmngr.
 
 @item uiserver-socket
 Return the name of the socket to connect to the user interface server.
 
 @item gpgconf-name
 Return the file name of the engine configuration tool.
 
 @item gpg-name
 Return the file name of the OpenPGP engine.
 
 @item gpgsm-name
 Return the file name of the CMS engine.
 
 @item g13-name
 Return the name of the file container encryption engine.
 
 @item gpg-wks-client-name
 Return the name of the Web Key Service tool.
 
 @end table
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_engine_check_version (@w{gpgme_protocol_t @var{protocol}})
 The function @code{gpgme_engine_check_version} verifies that the
 engine implementing the protocol @var{PROTOCOL} is installed in the
 expected path and meets the version requirement of @acronym{GPGME}.
 
 This function returns the error code @code{GPG_ERR_NO_ERROR} if the
 engine is available and @code{GPG_ERR_INV_ENGINE} if it is not.
 @end deftypefun
 
 
 @node Engine Information
 @section Engine Information
 @cindex engine, information about
 
 @deftp {Data type} {gpgme_engine_info_t}
 @tindex gpgme_protocol_t
 The @code{gpgme_engine_info_t} type specifies a pointer to a structure
 describing a crypto engine.  The structure contains the following
 elements:
 
 @table @code
 @item gpgme_engine_info_t next
 This is a pointer to the next engine info structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item gpgme_protocol_t protocol
 This is the protocol for which the crypto engine is used.  You can
 convert this to a string with @code{gpgme_get_protocol_name} for
 printing.
 
 @item const char *file_name
 This is a string holding the file name of the executable of the crypto
 engine.  Currently, it is never @code{NULL}, but using @code{NULL} is
 reserved for future use, so always check before you use it.
 
 @item const char *home_dir
 This is a string holding the directory name of the crypto engine's
 configuration directory.  If it is @code{NULL}, then the default
 directory is used.  See @code{gpgme_get_dirinfo} on how to get the
 default directory.
 
 @item const char *version
 This is a string containing the version number of the crypto engine.
 It might be @code{NULL} if the version number can not be determined,
 for example because the executable doesn't exist or is invalid.
 
 @item const char *req_version
 This is a string containing the minimum required version number of the
 crypto engine for @acronym{GPGME} to work correctly.  This is the
 version number that @code{gpgme_engine_check_version} verifies
 against.  Currently, it is never @code{NULL}, but using @code{NULL} is
 reserved for future use, so always check before you use it.
 @end table
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_get_engine_info (@w{gpgme_engine_info_t *@var{info}})
 The function @code{gpgme_get_engine_info} returns a linked list of
 engine info structures in @var{info}.  Each info structure describes
 the defaults of one configured backend.
 
 The memory for the info structures is allocated the first time this
 function is invoked, and must not be freed by the caller.
 
 This function returns the error code @code{GPG_ERR_NO_ERROR} if
 successful, and a system error if the memory could not be allocated.
 @end deftypefun
 
 Here is an example how you can provide more diagnostics if you receive
 an error message which indicates that the crypto engine is invalid.
 
 @example
 gpgme_ctx_t ctx;
 gpgme_error_t err;
 
 [...]
 
 if (gpgme_err_code (err) == GPG_ERR_INV_ENGINE)
   @{
     gpgme_engine_info_t info;
     err = gpgme_get_engine_info (&info);
     if (!err)
       @{
         while (info && info->protocol != gpgme_get_protocol (ctx))
           info = info->next;
         if (!info)
           fprintf (stderr, "GPGME compiled without support for protocol %s",
                    gpgme_get_protocol_name (info->protocol));
         else if (info->file_name && !info->version)
           fprintf (stderr, "Engine %s not installed properly",
                    info->file_name);
         else if (info->file_name && info->version && info->req_version)
           fprintf (stderr, "Engine %s version %s installed, "
                    "but at least version %s required", info->file_name,
                    info->version, info->req_version);
         else
           fprintf (stderr, "Unknown problem with engine for protocol %s",
                    gpgme_get_protocol_name (info->protocol));
       @}
   @}
 @end example
 
 
 @node Engine Configuration
 @section Engine Configuration
 @cindex engine, configuration of
 @cindex configuration of crypto backend
 
 You can change the configuration of a backend engine, and thus change
 the executable program and configuration directory to be used.  You
 can make these changes the default or set them for some contexts
 individually.
 
 @deftypefun gpgme_error_t gpgme_set_engine_info (@w{gpgme_protocol_t @var{proto}}, @w{const char *@var{file_name}}, @w{const char *@var{home_dir}})
 @since{1.1.0}
 
 The function @code{gpgme_set_engine_info} changes the default
 configuration of the crypto engine implementing the protocol
 @var{proto}.
 
 @var{file_name} is the file name of the executable program
 implementing this protocol, and @var{home_dir} is the directory name
 of the configuration directory for this crypto engine.  If
 @var{home_dir} is @code{NULL}, the engine's default will be used.
 
 The new defaults are not applied to already created GPGME contexts.
 
 This function returns the error code @code{GPG_ERR_NO_ERROR} if
 successful, or an error code on failure.
 @end deftypefun
 
 The functions @code{gpgme_ctx_get_engine_info} and
 @code{gpgme_ctx_set_engine_info} can be used to change the engine
 configuration per context.  @xref{Crypto Engine}.
 
 
 @node OpenPGP
 @section OpenPGP
 @cindex OpenPGP
 @cindex GnuPG
 @cindex protocol, GnuPG
 @cindex engine, GnuPG
 
 OpenPGP is implemented by GnuPG, the @acronym{GNU} Privacy Guard.
 This is the first protocol that was supported by @acronym{GPGME}.
 
 The OpenPGP protocol is specified by @code{GPGME_PROTOCOL_OpenPGP}.
 
 
 @node Cryptographic Message Syntax
 @section Cryptographic Message Syntax
 @cindex CMS
 @cindex cryptographic message syntax
 @cindex GpgSM
 @cindex protocol, CMS
 @cindex engine, GpgSM
 @cindex S/MIME
 @cindex protocol, S/MIME
 
 @acronym{CMS} is implemented by GpgSM, the S/MIME implementation for
 GnuPG.
 
 The @acronym{CMS} protocol is specified by @code{GPGME_PROTOCOL_CMS}.
 
 
 @node Assuan
 @section Assuan
 @cindex ASSUAN
 @cindex protocol, ASSUAN
 @cindex engine, ASSUAN
 
 Assuan is the RPC library used by the various @acronym{GnuPG}
 components.  The Assuan protocol allows one to talk to arbitrary
 Assuan servers using @acronym{GPGME}.  @xref{Using the Assuan
 protocol}.
 
 The ASSUAN protocol is specified by @code{GPGME_PROTOCOL_ASSUAN}.
 
 
 @node Algorithms
 @chapter Algorithms
 @cindex algorithms
 
 The crypto backends support a variety of algorithms used in public key
 cryptography.@footnote{Some engines also provide symmetric only
 encryption; see the description of the encryption function on how to use
 this.}  The following sections list the identifiers used to denote such
 an algorithm.
 
 @menu
 * Public Key Algorithms::         A list of all public key algorithms.
 * Hash Algorithms::               A list of all hash algorithms.
 @end menu
 
 
 @node Public Key Algorithms
 @section Public Key Algorithms
 @cindex algorithms, public key
 @cindex public key algorithms
 
 Public key algorithms are used for encryption, decryption, signing and
 verification of signatures.
 
 @deftp {Data type} {enum gpgme_pubkey_algo_t}
 @tindex gpgme_pubkey_algo_t
 The @code{gpgme_pubkey_algo_t} type specifies the set of all public key
 algorithms that are supported by @acronym{GPGME}.  Possible values
 are:
 
 @table @code
 @item GPGME_PK_RSA
 This value indicates the RSA (Rivest, Shamir, Adleman) algorithm.
 
 @item GPGME_PK_RSA_E
 Deprecated.  This value indicates the RSA (Rivest, Shamir, Adleman)
 algorithm for encryption and decryption only.
 
 @item GPGME_PK_RSA_S
 Deprecated.  This value indicates the RSA (Rivest, Shamir, Adleman)
 algorithm for signing and verification only.
 
 @item GPGME_PK_DSA
 This value indicates DSA, the Digital Signature Algorithm.
 
 @item GPGME_PK_ELG
 This value indicates ElGamal.
 
 @item GPGME_PK_ELG_E
 This value also indicates ElGamal and is used specifically in GnuPG.
 
 @item GPGME_PK_ECC
 @since{1.5.0}
 
 This value is a generic indicator for ellipic curve algorithms.
 
 @item GPGME_PK_ECDSA
 @since{1.3.0}
 
 This value indicates ECDSA, the Elliptic Curve Digital Signature
 Algorithm as defined by FIPS 186-2 and RFC-6637.
 
 @item GPGME_PK_ECDH
 @since{1.3.0}
 
 This value indicates ECDH, the Eliptic Curve Diffie-Hellmann
 encryption algorithm as defined by RFC-6637.
 
 @item GPGME_PK_EDDSA
 @since{1.7.0}
 
 This value indicates the EdDSA algorithm.
 
 @end table
 @end deftp
 
 @deftypefun {const char *} gpgme_pubkey_algo_name (@w{gpgme_pubkey_algo_t @var{algo}})
 The function @code{gpgme_pubkey_algo_name} returns a pointer to a
 statically allocated string containing a description of the public key
 algorithm @var{algo}.  This string can be used to output the name of
 the public key algorithm to the user.
 
 If @var{algo} is not a valid public key algorithm, @code{NULL} is
 returned.
 @end deftypefun
 
 @deftypefun {char *} gpgme_pubkey_algo_string (@w{gpgme_subkey_t @var{key}})
 @since{1.7.0}
 
 The function @code{gpgme_pubkey_algo_string} is a convenience function
 to build and return an algorithm string in the same way GnuPG does
 (e.g. ``rsa2048'' or ``ed25519'').  The caller must free the result
 using @code{gpgme_free}.  On error (e.g. invalid argument or memory
 exhausted), the function returns NULL and sets @code{ERRNO}.
 @end deftypefun
 
 
 @node Hash Algorithms
 @section Hash Algorithms
 @cindex algorithms, hash
 @cindex algorithms, message digest
 @cindex hash algorithms
 @cindex message digest algorithms
 
 Hash (message digest) algorithms are used to compress a long message
 to make it suitable for public key cryptography.
 
 @deftp {Data type} {enum gpgme_hash_algo_t}
 @tindex gpgme_hash_algo_t
 The @code{gpgme_hash_algo_t} type specifies the set of all hash algorithms
 that are supported by @acronym{GPGME}.  Possible values are:
 
 @table @code
 @item GPGME_MD_MD5
 @item GPGME_MD_SHA1
 @item GPGME_MD_RMD160
 @item GPGME_MD_MD2
 @item GPGME_MD_TIGER
 @item GPGME_MD_HAVAL
 @item GPGME_MD_SHA256
 @item GPGME_MD_SHA384
 @item GPGME_MD_SHA512
 @item GPGME_MD_SHA224
 @since{1.5.0}
 
 @item GPGME_MD_MD4
 @item GPGME_MD_CRC32
 @item GPGME_MD_CRC32_RFC1510
 @item GPGME_MD_CRC24_RFC2440
 @end table
 @end deftp
 
 @deftypefun {const char *} gpgme_hash_algo_name (@w{gpgme_hash_algo_t @var{algo}})
 The function @code{gpgme_hash_algo_name} returns a pointer to a
 statically allocated string containing a description of the hash
 algorithm @var{algo}.  This string can be used to output the name of
 the hash algorithm to the user.
 
 If @var{algo} is not a valid hash algorithm, @code{NULL} is returned.
 @end deftypefun
 
 
 @node Error Handling
 @chapter Error Handling
 @cindex error handling
 
 Many functions in @acronym{GPGME} can return an error if they fail.
 For this reason, the application should always catch the error
 condition and take appropriate measures, for example by releasing the
 resources and passing the error up to the caller, or by displaying a
 descriptive message to the user and cancelling the operation.
 
 Some error values do not indicate a system error or an error in the
 operation, but the result of an operation that failed properly.  For
 example, if you try to decrypt a tempered message, the decryption will
 fail.  Another error value actually means that the end of a data
 buffer or list has been reached.  The following descriptions explain
 for many error codes what they mean usually.  Some error values have
 specific meanings if returned by a certain functions.  Such cases are
 described in the documentation of those functions.
 
 @acronym{GPGME} uses the @code{libgpg-error} library.  This allows to
 share the error codes with other components of the GnuPG system, and
 thus pass error values transparently from the crypto engine, or some
 helper application of the crypto engine, to the user.  This way no
 information is lost.  As a consequence, @acronym{GPGME} does not use
 its own identifiers for error codes, but uses those provided by
 @code{libgpg-error}.  They usually start with @code{GPG_ERR_}.
 
 However, @acronym{GPGME} does provide aliases for the functions
 defined in libgpg-error, which might be preferred for name space
 consistency.
 
 @menu
 * Error Values::                  The error value and what it means.
 * Error Sources::                 A list of important error sources.
 * Error Codes::                   A list of important error codes.
 * Error Strings::                 How to get a descriptive string from a value.
 @end menu
 
 
 @node Error Values
 @section Error Values
 @cindex error values
 @cindex error codes
 @cindex error sources
 
 @deftp {Data type} {gpgme_err_code_t}
 The @code{gpgme_err_code_t} type is an alias for the @code{libgpg-error}
 type @code{gpg_err_code_t}.  The error code indicates the type of an
 error, or the reason why an operation failed.
 
 A list of important error codes can be found in the next section.
 @end deftp
 
 @deftp {Data type} {gpgme_err_source_t}
 The @code{gpgme_err_source_t} type is an alias for the
 @code{libgpg-error} type @code{gpg_err_source_t}.  The error source
 has not a precisely defined meaning.  Sometimes it is the place where
 the error happened, sometimes it is the place where an error was
 encoded into an error value.  Usually the error source will give an
 indication to where to look for the problem.  This is not always true,
 but it is attempted to achieve this goal.
 
 A list of important error sources can be found in the next section.
 @end deftp
 
 @deftp {Data type} {gpgme_error_t}
 The @code{gpgme_error_t} type is an alias for the @code{libgpg-error}
 type @code{gpg_error_t}.  An error value like this has always two
 components, an error code and an error source.  Both together form the
 error value.
 
 Thus, the error value can not be directly compared against an error
 code, but the accessor functions described below must be used.
 However, it is guaranteed that only 0 is used to indicate success
 (@code{GPG_ERR_NO_ERROR}), and that in this case all other parts of
 the error value are set to 0, too.
 
 Note that in @acronym{GPGME}, the error source is used purely for
 diagnostical purposes.  Only the error code should be checked to test
 for a certain outcome of a function.  The manual only documents the
 error code part of an error value.  The error source is left
 unspecified and might be anything.
 @end deftp
 
 @deftypefun {static inline gpgme_err_code_t} gpgme_err_code (@w{gpgme_error_t @var{err}})
 The static inline function @code{gpgme_err_code} returns the
 @code{gpgme_err_code_t} component of the error value @var{err}.  This
 function must be used to extract the error code from an error value in
 order to compare it with the @code{GPG_ERR_*} error code macros.
 @end deftypefun
 
 @deftypefun {static inline gpgme_err_source_t} gpgme_err_source (@w{gpgme_error_t @var{err}})
 The static inline function @code{gpgme_err_source} returns the
 @code{gpgme_err_source_t} component of the error value @var{err}.  This
 function must be used to extract the error source from an error value in
 order to compare it with the @code{GPG_ERR_SOURCE_*} error source macros.
 @end deftypefun
 
 @deftypefun {static inline gpgme_error_t} gpgme_err_make (@w{gpgme_err_source_t @var{source}}, @w{gpgme_err_code_t @var{code}})
 The static inline function @code{gpgme_err_make} returns the error
 value consisting of the error source @var{source} and the error code
 @var{code}.
 
 This function can be used in callback functions to construct an error
 value to return it to the library.
 @end deftypefun
 
 @deftypefun {static inline gpgme_error_t} gpgme_error (@w{gpgme_err_code_t @var{code}})
 The static inline function @code{gpgme_error} returns the error value
 consisting of the default error source and the error code @var{code}.
 
 For @acronym{GPGME} applications, the default error source is
 @code{GPG_ERR_SOURCE_USER_1}.  You can define
 @code{GPGME_ERR_SOURCE_DEFAULT} before including @file{gpgme.h} to
 change this default.
 
 This function can be used in callback functions to construct an error
 value to return it to the library.
 @end deftypefun
 
 The @code{libgpg-error} library provides error codes for all system
 error numbers it knows about.  If @var{err} is an unknown error
 number, the error code @code{GPG_ERR_UNKNOWN_ERRNO} is used.  The
 following functions can be used to construct error values from system
 errnor numbers.
 
 @deftypefun {gpgme_error_t} gpgme_err_make_from_errno (@w{gpgme_err_source_t @var{source}}, @w{int @var{err}})
 The function @code{gpgme_err_make_from_errno} is like
 @code{gpgme_err_make}, but it takes a system error like @code{errno}
 instead of a @code{gpgme_err_code_t} error code.
 @end deftypefun
 
 @deftypefun {gpgme_error_t} gpgme_error_from_errno (@w{int @var{err}})
 The function @code{gpgme_error_from_errno} is like @code{gpgme_error},
 but it takes a system error like @code{errno} instead of a
 @code{gpgme_err_code_t} error code.
 @end deftypefun
 
 Sometimes you might want to map system error numbers to error codes
 directly, or map an error code representing a system error back to the
 system error number.  The following functions can be used to do that.
 
 @deftypefun {gpgme_err_code_t} gpgme_err_code_from_errno (@w{int @var{err}})
 The function @code{gpgme_err_code_from_errno} returns the error code
 for the system error @var{err}.  If @var{err} is not a known system
 error, the function returns @code{GPG_ERR_UNKNOWN_ERRNO}.
 @end deftypefun
 
 @deftypefun {int} gpgme_err_code_to_errno (@w{gpgme_err_code_t @var{err}})
 The function @code{gpgme_err_code_to_errno} returns the system error
 for the error code @var{err}.  If @var{err} is not an error code
 representing a system error, or if this system error is not defined on
 this system, the function returns @code{0}.
 @end deftypefun
 
 
 @node Error Sources
 @section Error Sources
 @cindex error codes, list of
 
 The library @code{libgpg-error} defines an error source for every
 component of the GnuPG system.  The error source part of an error
 value is not well defined.  As such it is mainly useful to improve the
 diagnostic error message for the user.
 
 If the error code part of an error value is @code{0}, the whole error
 value will be @code{0}.  In this case the error source part is of
 course @code{GPG_ERR_SOURCE_UNKNOWN}.
 
 The list of error sources that might occur in applications using
 @acronym{GPGME} is:
 
 @table @code
 @item GPG_ERR_SOURCE_UNKNOWN
 The error source is not known.  The value of this error source is
 @code{0}.
 
 @item GPG_ERR_SOURCE_GPGME
 The error source is @acronym{GPGME} itself.  This is the default for
 errors that occur in the @acronym{GPGME} library.
 
 @item GPG_ERR_SOURCE_GPG
 The error source is GnuPG, which is the crypto engine used for the
 OpenPGP protocol.
 
 @item GPG_ERR_SOURCE_GPGSM
 The error source is GPGSM, which is the crypto engine used for the
 CMS protocol.
 
 @item GPG_ERR_SOURCE_GCRYPT
 The error source is @code{libgcrypt}, which is used by crypto engines
 to perform cryptographic operations.
 
 @item GPG_ERR_SOURCE_GPGAGENT
 The error source is @command{gpg-agent}, which is used by crypto
 engines to perform operations with the secret key.
 
 @item GPG_ERR_SOURCE_PINENTRY
 The error source is @command{pinentry}, which is used by
 @command{gpg-agent} to query the passphrase to unlock a secret key.
 
 @item GPG_ERR_SOURCE_SCD
 The error source is the SmartCard Daemon, which is used by
 @command{gpg-agent} to delegate operations with the secret key to a
 SmartCard.
 
 @item GPG_ERR_SOURCE_KEYBOX
 The error source is @code{libkbx}, a library used by the crypto
 engines to manage local keyrings.
 
 @item GPG_ERR_SOURCE_USER_1
 @item GPG_ERR_SOURCE_USER_2
 @item GPG_ERR_SOURCE_USER_3
 @item GPG_ERR_SOURCE_USER_4
 These error sources are not used by any GnuPG component and can be
 used by other software.  For example, applications using
 @acronym{GPGME} can use them to mark error values coming from callback
 handlers.  Thus @code{GPG_ERR_SOURCE_USER_1} is the default for errors
 created with @code{gpgme_error} and @code{gpgme_error_from_errno},
 unless you define @code{GPGME_ERR_SOURCE_DEFAULT} before including
 @file{gpgme.h}.
 @end table
 
 
 @node Error Codes
 @section Error Codes
 @cindex error codes, list of
 
 The library @code{libgpg-error} defines many error values.  Most of
 them are not used by @code{GPGME} directly, but might be returned by
 @acronym{GPGME} because it received them from the crypto engine.  The
 below list only includes such error codes that have a specific meaning
 in @code{GPGME}, or which are so common that you should know about
 them.
 
 @table @code
 @item GPG_ERR_EOF
 This value indicates the end of a list, buffer or file.
 
 @item GPG_ERR_NO_ERROR
 This value indicates success.  The value of this error code is
 @code{0}.  Also, it is guaranteed that an error value made from the
 error code @code{0} will be @code{0} itself (as a whole).  This means
 that the error source information is lost for this error code,
 however, as this error code indicates that no error occurred, this is
 generally not a problem.
 
 @item GPG_ERR_GENERAL
 This value means that something went wrong, but either there is not
 enough information about the problem to return a more useful error
 value, or there is no separate error value for this type of problem.
 
 @item GPG_ERR_ENOMEM
 This value means that an out-of-memory condition occurred.
 
 @item GPG_ERR_E...
 System errors are mapped to GPG_ERR_FOO where FOO is the symbol for
 the system error.
 
 @item GPG_ERR_INV_VALUE
 This value means that some user provided data was out of range.  This
 can also refer to objects.  For example, if an empty
 @code{gpgme_data_t} object was expected, but one containing data was
 provided, this error value is returned.
 
 @item GPG_ERR_UNUSABLE_PUBKEY
 This value means that some recipients for a message were invalid.
 
 @item GPG_ERR_UNUSABLE_SECKEY
 This value means that some signers were invalid.
 
 @item GPG_ERR_NO_DATA
 This value means that a @code{gpgme_data_t} object which was expected
 to have content was found empty.
 
 @item GPG_ERR_CONFLICT
 This value means that a conflict of some sort occurred.
 
 @item GPG_ERR_NOT_IMPLEMENTED
 This value indicates that the specific function (or operation) is not
 implemented.  This error should never happen.  It can only occur if
 you use certain values or configuration options which do not work,
 but for which we think that they should work at some later time.
 
 @item GPG_ERR_DECRYPT_FAILED
 This value indicates that a decryption operation was unsuccessful.
 
 @item GPG_ERR_BAD_PASSPHRASE
 This value means that the user did not provide a correct passphrase
 when requested.
 
 @item GPG_ERR_CANCELED
 This value means that the operation was canceled.
 
 @item GPG_ERR_INV_ENGINE
 This value means that the engine that implements the desired protocol
 is currently not available.  This can either be because the sources
 were configured to exclude support for this engine, or because the
 engine is not installed properly.
 
 @item GPG_ERR_AMBIGUOUS_NAME
 This value indicates that a user ID or other specifier did not specify
 a unique key.
 
 @item GPG_ERR_WRONG_KEY_USAGE
 This value indicates that a key is not used appropriately.
 
 @item GPG_ERR_CERT_REVOKED
 This value indicates that a key signature was revoced.
 
 @item GPG_ERR_CERT_EXPIRED
 This value indicates that a key signature expired.
 
 @item GPG_ERR_NO_CRL_KNOWN
 This value indicates that no certificate revocation list is known for
 the certificate.
 
 @item GPG_ERR_NO_POLICY_MATCH
 This value indicates that a policy issue occurred.
 
 @item GPG_ERR_NO_SECKEY
 This value indicates that no secret key for the user ID is available.
 
 @item GPG_ERR_MISSING_CERT
 This value indicates that a key could not be imported because the
 issuer certificate is missing.
 
 @item GPG_ERR_BAD_CERT_CHAIN
 This value indicates that a key could not be imported because its
 certificate chain is not good, for example it could be too long.
 
 @item GPG_ERR_UNSUPPORTED_ALGORITHM
 This value means a verification failed because the cryptographic
 algorithm is not supported by the crypto backend.
 
 @item GPG_ERR_BAD_SIGNATURE
 This value means a verification failed because the signature is bad.
 
 @item GPG_ERR_NO_PUBKEY
 This value means a verification failed because the public key is not
 available.
 
 @item GPG_ERR_USER_1
 @item GPG_ERR_USER_2
 @item ...
 @item GPG_ERR_USER_16
 These error codes are not used by any GnuPG component and can be
 freely used by other software.  Applications using @acronym{GPGME}
 might use them to mark specific errors returned by callback handlers
 if no suitable error codes (including the system errors) for
 these errors exist already.
 @end table
 
 
 @node Error Strings
 @section Error Strings
 @cindex error values, printing of
 @cindex error codes, printing of
 @cindex error sources, printing of
 @cindex error strings
 
 @deftypefun {const char *} gpgme_strerror (@w{gpgme_error_t @var{err}})
 The function @code{gpgme_strerror} returns a pointer to a statically
 allocated string containing a description of the error code contained
 in the error value @var{err}.  This string can be used to output a
 diagnostic message to the user.
 
 This function is not thread safe.  Use @code{gpgme_strerror_r} in
 multi-threaded programs.
 @end deftypefun
 
 
 @deftypefun {int} gpgme_strerror_r (@w{gpgme_error_t @var{err}}, @w{char *@var{buf}}, @w{size_t @var{buflen}})
 The function @code{gpgme_strerror_r} returns the error string for
 @var{err} in the user-supplied buffer @var{buf} of size @var{buflen}.
 This function is, in contrast to @code{gpgme_strerror}, thread-safe if
 a thread-safe @code{strerror_r} function is provided by the system.
 If the function succeeds, 0 is returned and @var{buf} contains the
 string describing the error.  If the buffer was not large enough,
 ERANGE is returned and @var{buf} contains as much of the beginning of
 the error string as fits into the buffer.
 @end deftypefun
 
 
 @deftypefun {const char *} gpgme_strsource (@w{gpgme_error_t @var{err}})
 The function @code{gpgme_strerror} returns a pointer to a statically
 allocated string containing a description of the error source
 contained in the error value @var{err}.  This string can be used to
 output a diagnostic message to the user.
 @end deftypefun
 
 The following example illustrates the use of @code{gpgme_strerror}:
 
 @example
 gpgme_ctx_t ctx;
 gpgme_error_t err = gpgme_new (&ctx);
 if (err)
   @{
     fprintf (stderr, "%s: creating GpgME context failed: %s: %s\n",
              argv[0], gpgme_strsource (err), gpgme_strerror (err));
     exit (1);
   @}
 @end example
 
 
 @node Exchanging Data
 @chapter Exchanging Data
 @cindex data, exchanging
 
 A lot of data has to be exchanged between the user and the crypto
 engine, like plaintext messages, ciphertext, signatures and
 information about the keys.  The technical details about exchanging
 the data information are completely abstracted by @acronym{GPGME}.
 The user provides and receives the data via @code{gpgme_data_t} objects,
 regardless of the communication protocol between @acronym{GPGME} and
 the crypto engine in use.
 
 @deftp {Data type} {gpgme_data_t}
 The @code{gpgme_data_t} type is a handle for a container for generic
 data, which is used by @acronym{GPGME} to exchange data with the user.
 @end deftp
 
 @code{gpgme_data_t} objects do not provide notifications on events.
 It is assumed that read and write operations are blocking until data
 is available.  If this is undesirable, the application must ensure
 that all GPGME data operations always have data available, for example
 by using memory buffers or files rather than pipes or sockets.  This
 might be relevant, for example, if the external event loop mechanism
 is used.
 
 @deftp {Data type} {gpgme_off_t}
 @since{1.4.1}
 
 On POSIX platforms the @code{gpgme_off_t} type is an alias for
 @code{off_t}; it may be used interchangeable.  On Windows platforms
 @code{gpgme_off_t} is defined as a long (i.e. 32 bit) for 32 bit
 Windows and as a 64 bit signed integer for 64 bit Windows.
 @end deftp
 
 @deftp {Data type} {gpgme_ssize_t}
 The @code{gpgme_ssize_t} type is an alias for @code{ssize_t}.  It has
 only been introduced to overcome portability problems pertaining to
 the declaration of @code{ssize_t} by different toolchains.
 @end deftp
 
 
 @menu
 * Creating Data Buffers::         Creating new data buffers.
 * Destroying Data Buffers::       Releasing data buffers.
 * Manipulating Data Buffers::     Operations on data buffers.
 @end menu
 
 
 @node Creating Data Buffers
 @section Creating Data Buffers
 @cindex data buffer, creation
 
 Data objects can be based on memory, files, or callback functions
 provided by the user.  Not all operations are supported by all
 objects.
 
 
 @menu
 * Memory Based Data Buffers::     Creating memory based data buffers.
 * File Based Data Buffers::       Creating file based data buffers.
 * Callback Based Data Buffers::   Creating callback based data buffers.
 @end menu
 
 
 @node Memory Based Data Buffers
 @subsection Memory Based Data Buffers
 
 Memory based data objects store all data in allocated memory.  This is
 convenient, but only practical for an amount of data that is a
 fraction of the available physical memory.  The data has to be copied
 from its source and to its destination, which can often be avoided by
 using one of the other data object
 
 @deftypefun gpgme_error_t gpgme_data_new (@w{gpgme_data_t *@var{dh}})
 The function @code{gpgme_data_new} creates a new @code{gpgme_data_t}
 object and returns a handle for it in @var{dh}.  The data object is
 memory based and initially empty.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{dh} is not a valid pointer, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_new_from_mem (@w{gpgme_data_t *@var{dh}}, @w{const char *@var{buffer}}, @w{size_t @var{size}}, @w{int @var{copy}})
 The function @code{gpgme_data_new_from_mem} creates a new
 @code{gpgme_data_t} object and fills it with @var{size} bytes starting
 from @var{buffer}.
 
 If @var{copy} is not zero, a private copy of the data is made.  If
 @var{copy} is zero, the data is taken from the specified buffer as
 needed, and the user has to ensure that the buffer remains valid for
 the whole life span of the data object.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{dh} or @var{buffer} is not a valid pointer, and
 @code{GPG_ERR_ENOMEM} if not enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_new_from_file (@w{gpgme_data_t *@var{dh}}, @w{const char *@var{filename}}, @w{int @var{copy}})
 The function @code{gpgme_data_new_from_file} creates a new
 @code{gpgme_data_t} object and fills it with the content of the file
 @var{filename}.
 
 If @var{copy} is not zero, the whole file is read in at initialization
 time and the file is not used anymore after that.  This is the only
 mode supported currently.  Later, a value of zero for @var{copy} might
 cause all reads to be delayed until the data is needed, but this is
 not yet implemented.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{dh} or @var{filename} is not a valid pointer,
 @code{GPG_ERR_NOT_IMPLEMENTED} if @var{code} is zero, and
 @code{GPG_ERR_ENOMEM} if not enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_new_from_filepart (@w{gpgme_data_t *@var{dh}}, @w{const char *@var{filename}}, @w{FILE *@var{fp}}, @w{off_t @var{offset}}, @w{size_t @var{length}})
 The function @code{gpgme_data_new_from_filepart} creates a new
 @code{gpgme_data_t} object and fills it with a part of the file specified
 by @var{filename} or @var{fp}.
 
 Exactly one of @var{filename} and @var{fp} must be non-zero, the other
 must be zero.  The argument that is not zero specifies the file from
 which @var{length} bytes are read into the data object, starting from
 @var{offset}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{dh} and exactly one of @var{filename} and @var{fp} is not a valid
 pointer, and @code{GPG_ERR_ENOMEM} if not enough memory is available.
 @end deftypefun
 
 
 @node File Based Data Buffers
 @subsection File Based Data Buffers
 
 File based data objects operate directly on file descriptors or
 streams.  Only a small amount of data is stored in core at any time,
 so the size of the data objects is not limited by @acronym{GPGME}.
 
 @deftypefun gpgme_error_t gpgme_data_new_from_fd (@w{gpgme_data_t *@var{dh}}, @w{int @var{fd}})
 The function @code{gpgme_data_new_from_fd} creates a new
 @code{gpgme_data_t} object and uses the file descriptor @var{fd} to read
 from (if used as an input data object) and write to (if used as an
 output data object).
 
 When using the data object as an input buffer, the function might read
 a bit more from the file descriptor than is actually needed by the
 crypto engine in the desired operation because of internal buffering.
 
 Note that GPGME assumes that the file descriptor is set to blocking
 mode.  Errors during I/O operations, except for EINTR, are usually
 fatal for crypto operations.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_new_from_stream (@w{gpgme_data_t *@var{dh}}, @w{FILE *@var{stream}})
 The function @code{gpgme_data_new_from_stream} creates a new
 @code{gpgme_data_t} object and uses the I/O stream @var{stream} to read
 from (if used as an input data object) and write to (if used as an
 output data object).
 
 When using the data object as an input buffer, the function might read
 a bit more from the stream than is actually needed by the crypto
 engine in the desired operation because of internal buffering.
 
 Note that GPGME assumes that the stream is in blocking mode.  Errors
 during I/O operations, except for EINTR, are usually fatal for crypto
 operations.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_new_from_estream (@w{gpgme_data_t *@var{dh}}, @w{gpgrt_stream_t @var{stream}})
 The function @code{gpgme_data_new_from_estream} creates a new
 @code{gpgme_data_t} object and uses the gpgrt stream @var{stream} to read
 from (if used as an input data object) and write to (if used as an
 output data object).
 
 When using the data object as an input buffer, the function might read
 a bit more from the stream than is actually needed by the crypto
 engine in the desired operation because of internal buffering.
 
 Note that GPGME assumes that the stream is in blocking mode.  Errors
 during I/O operations, except for EINTR, are usually fatal for crypto
 operations.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 
 @node Callback Based Data Buffers
 @subsection Callback Based Data Buffers
 
 If neither memory nor file based data objects are a good fit for your
 application, you can implement the functions a data object provides
 yourself and create a data object from these callback functions.
 
 @deftp {Data type} {ssize_t (*gpgme_data_read_cb_t) (@w{void *@var{handle}}, @w{void @var{*buffer}}, @w{size_t @var{size}})}
 @tindex gpgme_data_read_cb_t
 The @code{gpgme_data_read_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it wants to read data from a user-implemented
 data object.  The function should read up to @var{size} bytes from the
 current read position into the space starting at @var{buffer}.  The
 @var{handle} is provided by the user at data object creation time.
 
 Note that GPGME assumes that the read blocks until data is available.
 Errors during I/O operations, except for EINTR, are usually fatal for
 crypto operations.
 
 The function should return the number of bytes read, 0 on EOF, and -1
 on error.  If an error occurs, @var{errno} should be set to describe
 the type of the error.
 @end deftp
 
 @deftp {Data type} {ssize_t (*gpgme_data_write_cb_t) (@w{void *@var{handle}}, @w{const void @var{*buffer}}, @w{size_t @var{size}})}
 @tindex gpgme_data_write_cb_t
 The @code{gpgme_data_write_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it wants to write data to a user-implemented
 data object.  The function should write up to @var{size} bytes to the
 current write position from the space starting at @var{buffer}.  The
 @var{handle} is provided by the user at data object creation time.
 
 Note that GPGME assumes that the write blocks until data is available.
 Errors during I/O operations, except for EINTR, are usually fatal for
 crypto operations.
 
 The function should return the number of bytes written, and -1 on
 error.  If an error occurs, @var{errno} should be set to describe the
 type of the error.
 @end deftp
 
 @deftp {Data type} {off_t (*gpgme_data_seek_cb_t) (@w{void *@var{handle}}, @w{off_t @var{offset}}, @w{int @var{whence}})}
 @tindex gpgme_data_seek_cb_t
 The @code{gpgme_data_seek_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it wants to change the current read/write
 position in a user-implemented data object, just like the @code{lseek}
 function.
 
 The function should return the new read/write position, and -1 on
 error.  If an error occurs, @var{errno} should be set to describe the
 type of the error.
 @end deftp
 
 @deftp {Data type} {void (*gpgme_data_release_cb_t) (@w{void *@var{handle}})}
 @tindex gpgme_data_release_cb_t
 The @code{gpgme_data_release_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it wants to destroy a user-implemented data
 object.  The @var{handle} is provided by the user at data object
 creation time.
 @end deftp
 
 @deftp {Data type} {struct gpgme_data_cbs}
 This structure is used to store the data callback interface functions
 described above.  It has the following members:
 
 @table @code
 @item gpgme_data_read_cb_t read
 This is the function called by @acronym{GPGME} to read data from the
 data object.  It is only required for input data object.
 
 @item gpgme_data_write_cb_t write
 This is the function called by @acronym{GPGME} to write data to the
 data object.  It is only required for output data object.
 
 @item gpgme_data_seek_cb_t seek
 This is the function called by @acronym{GPGME} to change the current
 read/write pointer in the data object (if available).  It is optional.
 
 @item gpgme_data_release_cb_t release
 This is the function called by @acronym{GPGME} to release a data
 object.  It is optional.
 @end table
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_data_new_from_cbs (@w{gpgme_data_t *@var{dh}}, @w{gpgme_data_cbs_t @var{cbs}}, @w{void *@var{handle}})
 The function @code{gpgme_data_new_from_cbs} creates a new
 @code{gpgme_data_t} object and uses the user-provided callback functions
 to operate on the data object.
 
 The handle @var{handle} is passed as first argument to the callback
 functions.  This can be used to identify this data object.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 
 @node Destroying Data Buffers
 @section Destroying Data Buffers
 @cindex data buffer, destruction
 
 @deftypefun void gpgme_data_release (@w{gpgme_data_t @var{dh}})
 The function @code{gpgme_data_release} destroys the data object with
 the handle @var{dh}.  It releases all associated resources that were
 not provided by the user in the first place.
 @end deftypefun
 
 @deftypefun {char *} gpgme_data_release_and_get_mem (@w{gpgme_data_t @var{dh}}, @w{size_t *@var{length}})
 The function @code{gpgme_data_release_and_get_mem} is like
 @code{gpgme_data_release}, except that it returns the data buffer and
 its length that was provided by the object.
 
 The user has to release the buffer with @code{gpgme_free}.  In case
 the user provided the data buffer in non-copy mode, a copy will be
 made for this purpose.
 
 In case an error returns, or there is no suitable data buffer that can
 be returned to the user, the function will return @code{NULL}.  In any
 case, the data object @var{dh} is destroyed.
 @end deftypefun
 
 
 @deftypefun void gpgme_free (@w{void *@var{buffer}})
 @since{1.1.1}
 
 The function @code{gpgme_free} releases the memory returned by
 @code{gpgme_data_release_and_get_mem} and
 @code{gpgme_pubkey_algo_string}.  It should be used instead of the
 system libraries @code{free} function in case different allocators are
 used by a program.  This is often the case if gpgme is used under
 Windows as a DLL.
 @end deftypefun
 
 
 @node Manipulating Data Buffers
 @section Manipulating Data Buffers
 @cindex data buffer, manipulation
 
 Data buffers contain data and meta-data.  The following operations can
 be used to manipulate both.
 
 
 @menu
 * Data Buffer I/O Operations::    I/O operations on data buffers.
 * Data Buffer Meta-Data::         Meta-data manipulation of data buffers.
 * Data Buffer Convenience::       Convenience function for data buffers.
 @end menu
 
 
 @node Data Buffer I/O Operations
 @subsection Data Buffer I/O Operations
 @cindex data buffer, I/O operations
 @cindex data buffer, read
 @cindex data buffer, write
 @cindex data buffer, seek
 
 @deftypefun ssize_t gpgme_data_read (@w{gpgme_data_t @var{dh}}, @w{void *@var{buffer}}, @w{size_t @var{length}})
 The function @code{gpgme_data_read} reads up to @var{length} bytes
 from the data object with the handle @var{dh} into the space starting
 at @var{buffer}.
 
 If no error occurs, the actual amount read is returned.  If the end of
 the data object is reached, the function returns 0.
 
 In all other cases, the function returns -1 and sets @var{errno}.
 @end deftypefun
 
 @deftypefun ssize_t gpgme_data_write (@w{gpgme_data_t @var{dh}}, @w{const void *@var{buffer}}, @w{size_t @var{size}})
 The function @code{gpgme_data_write} writes up to @var{size} bytes
 starting from @var{buffer} into the data object with the handle
 @var{dh} at the current write position.
 
 The function returns the number of bytes actually written, or -1 if an
 error occurs.  If an error occurs, @var{errno} is set.
 @end deftypefun
 
 @deftypefun off_t gpgme_data_seek (@w{gpgme_data_t @var{dh}}, @w{off_t @var{offset}}, @w{int @var{whence}})
 The function @code{gpgme_data_seek} changes the current read/write
 position.
 
 The @var{whence} argument specifies how the @var{offset} should be
 interpreted.  It must be one of the following symbolic constants:
 
 @table @code
 @item SEEK_SET
 Specifies that @var{offset} is a count of characters from the
 beginning of the data object.
 
 @item SEEK_CUR
 Specifies that @var{offset} is a count of characters from the current
 file position.  This count may be positive or negative.
 
 @item SEEK_END
 Specifies that @var{offset} is a count of characters from the end of
 the data object.  A negative count specifies a position within the
 current extent of the data object; a positive count specifies a
 position past the current end.  If you set the position past the
 current end, and actually write data, you will extend the data object
 with zeros up to that position.
 @end table
 
 If successful, the function returns the resulting file position,
 measured in bytes from the beginning of the data object.  You can use
 this feature together with @code{SEEK_CUR} to read the current
 read/write position.
 
 If the function fails, -1 is returned and @var{errno} is set.
 @end deftypefun
 
 
 @node Data Buffer Meta-Data
 @subsection Data Buffer Meta-Data
 @cindex data buffer, meta-data
 @cindex data buffer, file name
 @cindex data buffer, encoding
 
 @deftypefun {char *} gpgme_data_get_file_name (@w{gpgme_data_t @var{dh}})
 @since{1.1.0}
 
 The function @code{gpgme_data_get_file_name} returns a pointer to a
 string containing the file name associated with the data object.  The
 file name will be stored in the output when encrypting or signing the
 data and will be returned to the user when decrypting or verifying the
 output data.
 
 If no error occurs, the string containing the file name is returned.
 Otherwise, @code{NULL} will be returned.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_data_set_file_name (@w{gpgme_data_t @var{dh}}, @w{const char *@var{file_name}})
 @since{1.1.0}
 
 The function @code{gpgme_data_set_file_name} sets the file name
 associated with the data object.  The file name will be stored in the
 output when encrypting or signing the data and will be returned to the
 user when decrypting or verifying the output data.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{dh} is not a valid pointer and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.
 @end deftypefun
 
 
 @deftp {Data type} {enum gpgme_data_encoding_t}
 @tindex gpgme_data_encoding_t
 The @code{gpgme_data_encoding_t} type specifies the encoding of a
 @code{gpgme_data_t} object.  For input data objects, the encoding is
 useful to give the backend a hint on the type of data.  For output
 data objects, the encoding can specify the output data format on
 certain operations.  Please note that not all backends support all
 encodings on all operations.  The following data types are available:
 
 @table @code
 @item GPGME_DATA_ENCODING_NONE
 This specifies that the encoding is not known.  This is the default
 for a new data object.  The backend will try its best to detect the
 encoding automatically.
 
 @item GPGME_DATA_ENCODING_BINARY
 This specifies that the data is encoding in binary form; i.e. there is
 no special encoding.
 
 @item GPGME_DATA_ENCODING_BASE64
 This specifies that the data is encoded using the Base-64 encoding
 scheme as used by @acronym{MIME} and other protocols.
 
 @item GPGME_DATA_ENCODING_ARMOR
 This specifies that the data is encoded in an armored form as used by
 OpenPGP and PEM.
 
 @item GPGME_DATA_ENCODING_MIME
 @since{1.7.0}
 
 This specifies that the data is encoded as a MIME part.
 
 @item GPGME_DATA_ENCODING_URL
 @since{1.2.0}
 
 The data is a list of linefeed delimited URLs.  This is only useful with
 @code{gpgme_op_import}.
 
 @item GPGME_DATA_ENCODING_URL0
 @since{1.2.0}
 
 The data is a list of binary zero delimited URLs.  This is only useful
 with @code{gpgme_op_import}.
 
 @item GPGME_DATA_ENCODING_URLESC
 @since{1.2.0}
 
 The data is a list of linefeed delimited URLs with all control and space
 characters percent escaped.  This mode is is not yet implemented.
 
 @end table
 @end deftp
 
 @deftypefun gpgme_data_encoding_t gpgme_data_get_encoding (@w{gpgme_data_t @var{dh}})
 The function @code{gpgme_data_get_encoding} returns the encoding of
 the data object with the handle @var{dh}.  If @var{dh} is not a valid
 pointer (e.g. @code{NULL}) @code{GPGME_DATA_ENCODING_NONE} is
 returned.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_set_encoding (@w{gpgme_data_t @var{dh}, gpgme_data_encoding_t @var{enc}})
 The function @code{gpgme_data_set_encoding} changes the encoding of
 the data object with the handle @var{dh} to @var{enc}.
 @end deftypefun
 
 @deftypefun {gpgme_error_t} gpgme_data_set_flag  @
             (@w{gpgme_data_t @var{dh}}, @
             @w{const char *@var{name}}, @
             @w{const char *@var{value}})
 
 @since{1.7.0}
 
 Some minor properties of the data object can be controlled with flags
 set by this function.  The properties are identified by the following
 values for @var{name}:
 
 @table @code
 @item size-hint
 The value is a decimal number with the length gpgme shall assume for
 this data object.  This is useful if the data is provided by callbacks
 or via file descriptors but the applications knows the total size of
 the data.  If this is set the OpenPGP engine may use this to decide on
 buffer allocation strategies and to provide a total value for its
 progress information.
 
 @end table
 
 This function returns @code{0} on success.
 @end deftypefun
 
 
 @node Data Buffer Convenience
 @subsection Data Buffer Convenience Functions
 @cindex data buffer, convenience
 @cindex type of data
 @cindex identify
 
 @deftp {Data type} {enum gpgme_data_type_t}
 @tindex gpgme_data_type_t
 @since{1.4.3}
 
 The @code{gpgme_data_type_t} type is used to return the detected type
 of the content of a data buffer.
 @end deftp
 
 @table @code
 @item GPGME_DATA_TYPE_INVALID
 This is returned by @code{gpgme_data_identify} if it was not possible
 to identify the data.  Reasons for this might be a non-seekable stream
 or a memory problem.  The value is 0.
 @item GPGME_DATA_TYPE_UNKNOWN
 The type of the data is not known.
 @item GPGME_DATA_TYPE_PGP_SIGNED
 The data is an OpenPGP signed message.  This may be a binary
 signature, a detached one or a cleartext signature.
 @item GPGME_DATA_TYPE_PGP_ENCRYPTED
 @since{1.7.0}
 
 The data is an OpenPGP encrypted message.
 @item GPGME_DATA_TYPE_PGP_SIGNATURE
 @since{1.7.0}
 
 The data is an OpenPGP detached signature.
 @item GPGME_DATA_TYPE_PGP_OTHER
 This is a generic OpenPGP message.  In most cases this will be
 encrypted data.
 @item GPGME_DATA_TYPE_PGP_KEY
 This is an OpenPGP key (private or public).
 @item GPGME_DATA_TYPE_CMS_SIGNED
 This is a CMS signed message.
 @item GPGME_DATA_TYPE_CMS_ENCRYPTED
 This is a CMS encrypted (enveloped data) message.
 @item GPGME_DATA_TYPE_CMS_OTHER
 This is used for other CMS message types.
 @item GPGME_DATA_TYPE_X509_CERT
 The data is a X.509 certificate
 @item GPGME_DATA_TYPE_PKCS12
 The data is a PKCS#12 message.  This is commonly used to exchange
 private keys for X.509.
 @end table
 
 @deftypefun gpgme_data_type_t gpgme_data_identify (@w{gpgme_data_t @var{dh}})
 @since{1.4.3}
 
 The function @code{gpgme_data_identify} returns the type of the data
 with the handle @var{dh}.  If it is not possible to perform the
 identification, the function returns zero
 (@code{GPGME_DATA_TYPE_INVALID}).  Note that depending on how the data
 object has been created the identification may not be possible or the
 data object may change its internal state (file pointer moved).  For
 file or memory based data object, the state should not change.
 @end deftypefun
 
 
 @c
 @c    Chapter Contexts
 @c
 @node Contexts
 @chapter Contexts
 @cindex context
 
 All cryptographic operations in @acronym{GPGME} are performed within a
 context, which contains the internal state of the operation as well as
 configuration parameters.  By using several contexts you can run
 several cryptographic operations in parallel, with different
 configuration.
 
 @deftp {Data type} {gpgme_ctx_t}
 The @code{gpgme_ctx_t} type is a handle for a @acronym{GPGME} context,
 which is used to hold the configuration, status and result of
 cryptographic operations.
 @end deftp
 
 @menu
 * Creating Contexts::             Creating new @acronym{GPGME} contexts.
 * Destroying Contexts::           Releasing @acronym{GPGME} contexts.
 * Result Management::             Managing the result of crypto operations.
 * Context Attributes::            Setting properties of a context.
 * Key Management::                Managing keys with @acronym{GPGME}.
 * Crypto Operations::             Using a context for cryptography.
 * Miscellaneous::                 Miscellaneous operations
 * Run Control::                   Controlling how operations are run.
 @end menu
 
 
 @node Creating Contexts
 @section Creating Contexts
 @cindex context, creation
 
 @deftypefun gpgme_error_t gpgme_new (@w{gpgme_ctx_t *@var{ctx}})
 The function @code{gpgme_new} creates a new @code{gpgme_ctx_t} object
 and returns a handle for it in @var{ctx}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 context was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, and @code{GPG_ERR_ENOMEM} if not
 enough memory is available.  Also, it returns
 @code{GPG_ERR_NOT_OPERATIONAL} if @code{gpgme_check_version} was not
 called to initialize GPGME, and @code{GPG_ERR_SELFTEST_FAILED} if a
 selftest failed.  Currently, the only selftest is for Windows MingW32
 targets to see if @code{-mms-bitfields} was used (as required).
 @end deftypefun
 
 
 @node Destroying Contexts
 @section Destroying Contexts
 @cindex context, destruction
 
 @deftypefun void gpgme_release (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_release} destroys the context with the handle
 @var{ctx} and releases all associated resources.
 @end deftypefun
 
 
 @node Result Management
 @section Result Management
 @cindex context, result of operation
 
 The detailed result of an operation is returned in operation-specific
 structures such as @code{gpgme_decrypt_result_t}.  The corresponding
 retrieval functions such as @code{gpgme_op_decrypt_result} provide
 static access to the results after an operation completes.  Those
 structures shall be considered read-only and an application must not
 allocate such a structure on its own.  The following interfaces make
 it possible to detach a result structure from its associated context
 and give it a lifetime beyond that of the current operation or
 context.
 
 @deftypefun void gpgme_result_ref (@w{void *@var{result}})
 @since{1.2.0}
 
 The function @code{gpgme_result_ref} acquires an additional reference
 for the result @var{result}, which may be of any type
 @code{gpgme_*_result_t}.  As long as the user holds a reference, the
 result structure is guaranteed to be valid and unmodified.
 @end deftypefun
 
 @deftypefun void gpgme_result_unref (@w{void *@var{result}})
 @since{1.2.0}
 
 The function @code{gpgme_result_unref} releases a reference for the
 result @var{result}.  If this was the last reference, the result
 structure will be destroyed and all resources associated to it will be
 released.
 @end deftypefun
 
 Note that a context may hold its own references to result structures,
 typically until the context is destroyed or the next operation is
 started.  In fact, these references are accessed through the
 @code{gpgme_op_*_result} functions.
 
 
 @node Context Attributes
 @section Context Attributes
 @cindex context, attributes
 
 @menu
 * Protocol Selection::            Selecting the protocol used by a context.
 * Crypto Engine::                 Configuring the crypto engine.
 * Setting the Sender::            How to tell the engine the sender.
 * ASCII Armor::                   Requesting @acronym{ASCII} armored output.
 * Text Mode::                     Choosing canonical text mode.
 * Offline Mode::                  Choosing offline mode.
 * Pinentry Mode::                 Choosing the pinentry mode.
 * Included Certificates::         Including a number of certificates.
 * Key Listing Mode::              Selecting key listing mode.
 * Passphrase Callback::           Getting the passphrase from the user.
 * Progress Meter Callback::       Being informed about the progress.
 * Status Message Callback::       Status messages received from gpg.
 * Context Flags::                 Additional flags for a context.
 * Locale::                        Setting the locale of a context.
 * Additional Logs::               Additional logs of a context.
 @end menu
 
 
 @node Protocol Selection
 @subsection Protocol Selection
 @cindex context, selecting protocol
 @cindex protocol, selecting
 
 @deftypefun gpgme_error_t gpgme_set_protocol (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_protocol_t @var{proto}})
 The function @code{gpgme_set_protocol} sets the protocol used within
 the context @var{ctx} to @var{proto}.  All crypto operations will be
 performed by the crypto engine configured for that protocol.
 @xref{Protocols and Engines}.
 
 Setting the protocol with @code{gpgme_set_protocol} does intentionally
 not check if the crypto engine for that protocol is available and
 installed correctly.  @xref{Engine Version Check}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 protocol could be set successfully, and @code{GPG_ERR_INV_VALUE} if
 @var{protocol} is not a valid protocol.
 @end deftypefun
 
 @deftypefun gpgme_protocol_t gpgme_get_protocol (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_get_protocol} retrieves the protocol currently
 use with the context @var{ctx}.
 @end deftypefun
 
 
 @node Crypto Engine
 @subsection Crypto Engine
 @cindex context, configuring engine
 @cindex engine, configuration per context
 
 The following functions can be used to set and retrieve the
 configuration of the crypto engines of a specific context.  The
 default can also be retrieved without any particular context.
 @xref{Engine Information}.  The default can also be changed globally.
 @xref{Engine Configuration}.
 
 @deftypefun gpgme_engine_info_t gpgme_ctx_get_engine_info (@w{gpgme_ctx_t @var{ctx}})
 @since{1.1.0}
 
 The function @code{gpgme_ctx_get_engine_info} returns a linked list of
 engine info structures.  Each info structure describes the
 configuration of one configured backend, as used by the context
 @var{ctx}.
 
 The result is valid until the next invocation of
 @code{gpgme_ctx_set_engine_info} for this particular context.
 
 This function can not fail.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_ctx_set_engine_info (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_protocol_t @var{proto}}, @w{const char *@var{file_name}}, @w{const char *@var{home_dir}})
 @since{1.1.0}
 
 The function @code{gpgme_ctx_set_engine_info} changes the
 configuration of the crypto engine implementing the protocol
 @var{proto} for the context @var{ctx}.
 
 @var{file_name} is the file name of the executable program
 implementing this protocol, and @var{home_dir} is the directory name
 of the configuration directory for this crypto engine.  If
 @var{home_dir} is @code{NULL}, the engine's default will be used.
 
 Currently this function must be used before starting the first crypto
 operation.  It is unspecified if and when the changes will take effect
 if the function is called after starting the first operation on the
 context @var{ctx}.
 
 This function returns the error code @code{GPG_ERR_NO_ERROR} if
 successful, or an error code on failure.
 @end deftypefun
 
 
 @node Setting the Sender
 @subsection How to tell the engine the sender.
 @cindex context, sender
 @cindex sender
 @cindex From:
 
 Some engines can make use of the sender’s address, for example to
 figure out the best user id in certain trust models.  For verification
 and signing of mails, it is thus suggested to let the engine know the
 sender ("From:") address.  @acronym{GPGME} provides two functions to
 accomplish that.  Note that the esoteric use of multiple "From:"
 addresses is not supported.
 
 @deftypefun gpgme_error_t gpgme_set_sender @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{int @var{address}})
 
 @since{1.8.0}
 
 The function @code{gpgme_set_sender} specifies the sender address for
 use in sign and verify operations.  @var{address} is expected to be
 the ``addr-spec'' part of an address but my also be a complete mailbox
 address, in which case this function extracts the ``addr-spec'' from
 it.  Using @code{NULL} for @var{address} clears the sender address.
 
 The function returns 0 on success or an error code on failure.  The
 most likely failure is that no valid ``addr-spec'' was found in
 @var{address}.
 
 @end deftypefun
 
 @deftypefun @w{const char *} gpgme_get_sender @
       (@w{gpgme_ctx_t @var{ctx}})
 
 @since{1.8.0}
 
 The function @code{gpgme_get_sender} returns the current sender
 address from the context, or NULL if none was set.  The returned
 value is valid as long as the @var{ctx} is valid and
 @code{gpgme_set_sender} has not been called again.
 
 @end deftypefun
 
 
 
 @c FIXME: Unfortunately, using @acronym here breaks texi2dvi.
 @node ASCII Armor
 @subsection @acronym{ASCII} Armor
 @cindex context, armor mode
 @cindex @acronym{ASCII} armor
 @cindex armor mode
 
 @deftypefun void gpgme_set_armor (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{yes}})
 The function @code{gpgme_set_armor} specifies if the output should be
 @acronym{ASCII} armored.  By default, output is not @acronym{ASCII}
 armored.
 
 @acronym{ASCII} armored output is disabled if @var{yes} is zero, and
 enabled otherwise.
 @end deftypefun
 
 @deftypefun int gpgme_get_armor (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_get_armor} returns 1 if the output is
 @acronym{ASCII} armored, and @code{0} if it is not, or if @var{ctx} is
 not a valid pointer.
 @end deftypefun
 
 
 @node Text Mode
 @subsection Text Mode
 @cindex context, text mode
 @cindex text mode
 @cindex canonical text mode
 
 @deftypefun void gpgme_set_textmode (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{yes}})
 The function @code{gpgme_set_textmode} specifies if canonical text mode
 should be used.  By default, text mode is not used.
 
 Text mode is for example used for the RFC2015 signatures; note that
 the updated RFC 3156 mandates that the mail user agent does some
 preparations so that text mode is not needed anymore.
 
 This option is only relevant to the OpenPGP crypto engine, and ignored
 by all other engines.
 
 Canonical text mode is disabled if @var{yes} is zero, and enabled
 otherwise.
 @end deftypefun
 
 @deftypefun int gpgme_get_textmode (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_get_textmode} returns 1 if canonical text
 mode is enabled, and @code{0} if it is not, or if @var{ctx} is not a
 valid pointer.
 @end deftypefun
 
 
 @node Offline Mode
 @subsection Offline Mode
 @cindex context, offline mode
 @cindex offline mode
 
 @deftypefun void gpgme_set_offline (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{yes}})
 @since{1.6.0}
 
 The function @code{gpgme_set_offline} specifies if offline mode should
 be used.  Offline mode is disabled if @var{yes} is zero, and enabled
 otherwise.  By default, offline mode is disabled.
 
 The details of the offline mode depend on the used protocol and its
 backend engine.  It may eventually be extended to be more stricter and
 for example completely disable the use of Dirmngr for any engine.
 
 For the CMS protocol the offline mode specifies whether Dirmngr shall
 be used to do additional validation that might require connecting
 external services (e.g. CRL / OCSP checks).  Here the offline mode
 only affects the keylist mode @code{GPGME_KEYLIST_MODE_VALIDATE}.
 
 For the OpenPGP protocol offline mode entirely disables the use of the
 Dirmngr and will thus guarantee that no network connections are done
 as part of an operation on this context.  It has only an effect with
 GnuPG versions 2.1.23 or later.
 
 For all other protocols the offline mode is currently ignored.
 
 @end deftypefun
 
 @deftypefun int gpgme_get_offline (@w{gpgme_ctx_t @var{ctx}})
 @since{1.6.0}
 
 The function @code{gpgme_get_offline} returns 1 if offline
 mode is enabled, and @code{0} if it is not, or if @var{ctx} is not a
 valid pointer.
 @end deftypefun
 
 
 @node Pinentry Mode
 @subsection Pinentry Mode
 @cindex context, pinentry mode
 @cindex pinentry mode
 
 @deftypefun gpgme_error_t gpgme_set_pinentry_mode (@w{gpgme_ctx_t @var{ctx}},
 @w{gpgme_pinentry_mode_t @var{mode}})
 
 @since{1.4.0}
 
 The function @code{gpgme_set_pinentry_mode} specifies the pinentry mode
 to be used.
 
 For GnuPG >= 2.1 this option is required to be set to
 @code{GPGME_PINENTRY_MODE_LOOPBACK} to enable the passphrase callback
 mechanism in GPGME through @code{gpgme_set_passphrase_cb}.
 @end deftypefun
 
 @deftypefun gpgme_pinentry_mode_t gpgme_get_pinentry_mode (@w{gpgme_ctx_t @var{ctx}})
 @since{1.4.0}
 
 The function @code{gpgme_get_pinenty_mode} returns the
 mode set for the context.
 @end deftypefun
 
 @deftp {Data type} {enum gpgme_pinentry_mode_t}
 @tindex gpgme_pinentry_mode_t
 @since{1.4.0}
 
 The @code{gpgme_minentry_mode_t} type specifies the set of possible pinentry
 modes that are supported by @acronym{GPGME} if GnuPG >= 2.1 is used.
 The following modes are supported:
 
 @table @code
 @item GPGME_PINENTRY_MODE_DEFAULT
 @since{1.4.0}
 
 Use the default of the agent, which is ask.
 
 @item GPGME_PINENTRY_MODE_ASK
 @since{1.4.0}
 
 Force the use of the Pinentry.
 
 @item GPGME_PINENTRY_MODE_CANCEL
 @since{1.4.0}
 
 Emulate use of Pinentry's cancel button.
 
 @item GPGME_PINENTRY_MODE_ERROR
 @since{1.4.0}
 
 Return a Pinentry error @code{No Pinentry}.
 
 @item GPGME_PINENTRY_MODE_LOOPBACK
 @since{1.4.0}
 
 Redirect Pinentry queries to the caller.
 This enables the use of @code{gpgme_set_passphrase_cb} because pinentry
 queries are redirected to gpgme.
 
 Note: For 2.1.0 - 2.1.12 this mode requires @code{allow-loopback-pinentry}
 to be enabled in the @file{gpg-agent.conf} or an agent started with that option.
 
 @end table
 @end deftp
 
 
 @node Included Certificates
 @subsection Included Certificates
 @cindex certificates, included
 
 @deftypefun void gpgme_set_include_certs (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{nr_of_certs}})
 The function @code{gpgme_set_include_certs} specifies how many
 certificates should be included in an S/MIME signed message.  By
 default, only the sender's certificate is included.  The possible
 values of @var{nr_of_certs} are:
 
 @table @code
 @item GPGME_INCLUDE_CERTS_DEFAULT
 @since{1.0.3}
 
 Fall back to the default of the crypto backend.  This is the default
 for GPGME.
 @item -2
 Include all certificates except the root certificate.
 @item -1
 Include all certificates.
 @item 0
 Include no certificates.
 @item 1
 Include the sender's certificate only.
 @item n
 Include the first n certificates of the certificates path, starting
 from the sender's certificate.  The number @code{n} must be positive.
 @end table
 
 Values of @var{nr_of_certs} smaller than -2 are undefined.
 
 This option is only relevant to the CMS crypto engine, and ignored by
 all other engines.
 @end deftypefun
 
 @deftypefun int gpgme_get_include_certs (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_get_include_certs} returns the number of
 certificates to include into an S/MIME signed message.
 @end deftypefun
 
 
 @node Key Listing Mode
 @subsection Key Listing Mode
 @cindex key listing mode
 @cindex key listing, mode of
 
 @deftypefun gpgme_error_t gpgme_set_keylist_mode (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_keylist_mode_t @var{mode}})
 The function @code{gpgme_set_keylist_mode} changes the default
 behaviour of the key listing functions.  The value in @var{mode} is a
 bitwise-or combination of one or multiple of the following bit values:
 
 @table @code
 @item GPGME_KEYLIST_MODE_LOCAL
 The @code{GPGME_KEYLIST_MODE_LOCAL} symbol specifies that the local
 keyring should be searched for keys in the keylisting operation.  This
 is the default.
 
 Using only this option results in a @code{--list-keys}.
 
 @item GPGME_KEYLIST_MODE_EXTERN
 The @code{GPGME_KEYLIST_MODE_EXTERN} symbol specifies that an external
 source should be searched for keys in the keylisting operation.  The
 type of external source is dependent on the crypto engine used and
 whether it is combined with @code{GPGME_KEYLIST_MODE_LOCAL}.  For
 example, it can be a remote keyserver or LDAP certificate server.
 
 Using only this option results in a @code{--search-keys} for
 @code{GPGME_PROTOCOL_OpenPGP} and something similar to
 @code{--list-external-keys} for @code{GPGME_PROTOCOL_CMS}.
 
 @item GPGME_KEYLIST_MODE_LOCATE
 This is a shortcut for the combination of
 @code{GPGME_KEYLIST_MODE_LOCAL} and @code{GPGME_KEYLIST_MODE_EXTERN}, which
 results in a @code{--locate-keys} for @code{GPGME_PROTOCOL_OpenPGP}.
 
 @item GPGME_KEYLIST_MODE_SIGS
 The @code{GPGME_KEYLIST_MODE_SIGS} symbol specifies that the key
 signatures should be included in the listed keys.
 
 @item GPGME_KEYLIST_MODE_SIG_NOTATIONS
 @since{1.1.1}
 
 The @code{GPGME_KEYLIST_MODE_SIG_NOTATIONS} symbol specifies that the
 signature notations on key signatures should be included in the listed
 keys.  This only works if @code{GPGME_KEYLIST_MODE_SIGS} is also
 enabled.
 
 @item GPGME_KEYLIST_MODE_WITH_TOFU
 @since{1.7.0}
 
 The @code{GPGME_KEYLIST_MODE_WITH_TOFU} symbol specifies that
 information pertaining to the TOFU trust model should be included in
 the listed keys.
 
 @item GPGME_KEYLIST_MODE_WITH_KEYGRIP
 @since{1.14.0}
 
 The @code{GPGME_KEYLIST_MODE_WITH_KEYRIP} symbol specifies that the
 keygrip is always included in the listing.  The default depends on the
 version of the backend and the used protocol.
 
 @item GPGME_KEYLIST_MODE_WITH_SECRET
 @since{1.5.1}
 
 The @code{GPGME_KEYLIST_MODE_WITH_SECRET} returns information about
 the presence of a corresponding secret key in a public key listing.  A
 public key listing with this mode is slower than a standard listing
 but can be used instead of a second run to list the secret keys.  This
 is only supported for GnuPG versions >= 2.1.  Note that using this
 option also makes sure that the keygrip is available in the output.
 
 @item GPGME_KEYLIST_MODE_EPHEMERAL
 @since{1.2.0}
 
 The @code{GPGME_KEYLIST_MODE_EPHEMERAL} symbol specifies that keys
 flagged as ephemeral are included in the listing.
 
 @item GPGME_KEYLIST_MODE_VALIDATE
 @since{0.4.5}
 
 The @code{GPGME_KEYLIST_MODE_VALIDATE} symbol specifies that the
 backend should do key or certificate validation and not just get the
 validity information from an internal cache.  This might be an
 expensive operation and is in general not useful.  Currently only
 implemented for the S/MIME backend and ignored for other backends.
 
 @end table
 
 At least one of @code{GPGME_KEYLIST_MODE_LOCAL} and
 @code{GPGME_KEYLIST_MODE_EXTERN} must be specified.  For future binary
 compatibility, you should get the current mode with
 @code{gpgme_get_keylist_mode} and modify it by setting or clearing the
 appropriate bits, and then using that calculated value in the
 @code{gpgme_set_keylisting_mode} operation.  This will leave all other
 bits in the mode value intact (in particular those that are not used
 in the current version of the library).
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 mode could be set correctly, and @code{GPG_ERR_INV_VALUE} if @var{ctx}
 is not a valid pointer or @var{mode} is not a valid mode.
 @end deftypefun
 
 
 @deftypefun gpgme_keylist_mode_t gpgme_get_keylist_mode (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_get_keylist_mode} returns the current key
 listing mode of the context @var{ctx}.  This value can then be
 modified and used in a subsequent @code{gpgme_set_keylist_mode}
 operation to only affect the desired bits (and leave all others
 intact).
 
 The function returns 0 if @var{ctx} is not a valid pointer, and the
 current mode otherwise.  Note that 0 is not a valid mode value.
 @end deftypefun
 
 
 @node Passphrase Callback
 @subsection Passphrase Callback
 @cindex callback, passphrase
 @cindex passphrase callback
 
 @deftp {Data type} {gpgme_error_t (*gpgme_passphrase_cb_t)(void *@var{hook}, const char *@var{uid_hint}, const char *@var{passphrase_info}, @w{int @var{prev_was_bad}}, @w{int @var{fd}})}
 @tindex gpgme_passphrase_cb_t
 The @code{gpgme_passphrase_cb_t} type is the type of functions usable as
 passphrase callback function.
 
 The argument @var{uid_hint} might contain a string that gives an
 indication for which user ID the passphrase is required.  If this is
 not available, or not applicable (in the case of symmetric encryption,
 for example), @var{uid_hint} will be @code{NULL}.
 
 The argument @var{passphrase_info}, if not @code{NULL}, will give
 further information about the context in which the passphrase is
 required.  This information is engine and operation specific.
 
 If this is the repeated attempt to get the passphrase, because
 previous attempts failed, then @var{prev_was_bad} is 1, otherwise it
 will be 0.
 
 The user must write the passphrase, followed by a newline character,
 to the file descriptor @var{fd}.  The function @code{gpgme_io_writen}
 should be used for the write operation.  Note that if the user returns
 0 to indicate success, the user must at least write a newline
 character before returning from the callback.
 
 If an error occurs, return the corresponding @code{gpgme_error_t}
 value.  You can use the error code @code{GPG_ERR_CANCELED} to abort
 the operation.  Otherwise, return @code{0}.
 
 Note: The passphrase_cb only works with GnuPG 1.x and 2.1.x and not
 with the 2.0.x series. See @code{gpgme_set_pinentry_mode} for more
 details on 2.1.x usage.
 @end deftp
 
 @deftypefun void gpgme_set_passphrase_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_passphrase_cb_t @var{passfunc}}, @w{void *@var{hook_value}})
 The function @code{gpgme_set_passphrase_cb} sets the function that is
 used when a passphrase needs to be provided by the user to
 @var{passfunc}.  The function @var{passfunc} needs to implemented by
 the user, and whenever it is called, it is called with its first
 argument being @var{hook_value}.  By default, no passphrase callback
 function is set.
 
 Not all crypto engines require this callback to retrieve the
 passphrase.  It is better if the engine retrieves the passphrase from
 a trusted agent (a daemon process), rather than having each user to
 implement their own passphrase query.  Some engines do not even
 support an external passphrase callback at all, in this case the error
 code @code{GPG_ERR_NOT_SUPPORTED} is returned.
 
 For GnuPG >= 2.1 the pinentry mode has to be set to
 @code{GPGME_PINENTRY_MODE_LOOPBACK} to enable the passphrase callback.
 See @code{gpgme_set_pinentry_mode}.
 
 The user can disable the use of a passphrase callback function by
 calling @code{gpgme_set_passphrase_cb} with @var{passfunc} being
 @code{NULL}.
 @end deftypefun
 
 @deftypefun void gpgme_get_passphrase_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_passphrase_cb_t *@var{passfunc}}, @w{void **@var{hook_value}})
 The function @code{gpgme_get_passphrase_cb} returns the function that
 is used when a passphrase needs to be provided by the user in
 @var{*passfunc}, and the first argument for this function in
 @var{*hook_value}.  If no passphrase callback is set, or @var{ctx} is
 not a valid pointer, @code{NULL} is returned in both variables.
 
 @var{passfunc} or @var{hook_value} can be @code{NULL}.  In this case,
 the corresponding value will not be returned.
 @end deftypefun
 
 
 @node Progress Meter Callback
 @subsection Progress Meter Callback
 @cindex callback, progress meter
 @cindex progress meter callback
 
 @deftp {Data type} {void (*gpgme_progress_cb_t)(void *@var{hook}, const char *@var{what}, int @var{type}, int @var{current}, int @var{total})}
 @tindex gpgme_progress_cb_t
 The @code{gpgme_progress_cb_t} type is the type of functions usable as
 progress callback function.
 
 The arguments are specific to the crypto engine.  More information
 about the progress information returned from the GnuPG engine can be
 found in the GnuPG source code in the file @file{doc/DETAILS} in the
 section PROGRESS.
 @end deftp
 
 @deftypefun void gpgme_set_progress_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_progress_cb_t @var{progfunc}}, @w{void *@var{hook_value}})
 The function @code{gpgme_set_progress_cb} sets the function that is
 used when progress information about a cryptographic operation is
 available.  The function @var{progfunc} needs to implemented by the
 user, and whenever it is called, it is called with its first argument
 being @var{hook_value}.  By default, no progress callback function
 is set.
 
 Setting a callback function allows an interactive program to display
 progress information about a long operation to the user.
 
 The user can disable the use of a progress callback function by
 calling @code{gpgme_set_progress_cb} with @var{progfunc} being
 @code{NULL}.
 @end deftypefun
 
 @deftypefun void gpgme_get_progress_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_progress_cb_t *@var{progfunc}}, @w{void **@var{hook_value}})
 The function @code{gpgme_get_progress_cb} returns the function that is
 used to inform the user about the progress made in @var{*progfunc},
 and the first argument for this function in @var{*hook_value}.  If no
 progress callback is set, or @var{ctx} is not a valid pointer,
 @code{NULL} is returned in both variables.
 
 @var{progfunc} or @var{hook_value} can be @code{NULL}.  In this case,
 the corresponding value will not be returned.
 @end deftypefun
 
 
 @node Status Message Callback
 @subsection Status Message Callback
 @cindex callback, status message
 @cindex status message callback
 
 @deftp {Data type} {gpgme_error_t (*gpgme_status_cb_t)(void *@var{hook}, const char *@var{keyword}, const char *@var{args})}
 @tindex gpgme_status_cb_t
 The @code{gpgme_status_cb_t} type is the type of function usable as
 a status message callback function.
 
 The argument @var{keyword} is the name of the status message while the
 @var{args} argument contains any arguments for the status message.
 
 If an error occurs, return the corresponding @code{gpgme_error_t}
 value. Otherwise, return @code{0}.
 @end deftp
 
 @deftypefun void gpgme_set_status_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_status_cb_t @var{statusfunc}}, @w{void *@var{hook_value}})
 @since{1.6.0}
 
 The function @code{gpgme_set_status_cb} sets the function that is used when a
 status message is received from gpg to @var{statusfunc}. The function
 @var{statusfunc} needs to be implemented by the user, and whenever it is
 called, it is called with its first argument being @var{hook_value}.  By
 default, no status message callback function is set.
 
 The user can disable the use of a status message callback function by calling
 @code{gpgme_set_status_cb} with @var{statusfunc} being @code{NULL}.
 @end deftypefun
 
 @deftypefun void gpgme_get_status_cb (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_status_cb_t *@var{statusfunc}}, @w{void **@var{hook_value}})
 @since{1.6.0}
 
 The function @code{gpgme_get_status_cb} returns the function that is used to
 process status messages from gpg in @var{*statusfunc}, and the first argument
 for this function in @var{*hook_value}.  If no status message callback is set,
 or @var{ctx} is not a valid pointer, @code{NULL} is returned in both
 variables.
 @end deftypefun
 
 @node Context Flags
 @subsection Context Flags
 @cindex flags, of a context
 
 @deftypefun {gpgme_error_t} gpgme_set_ctx_flag  @
             (@w{gpgme_ctx_t @var{ctx}}, @
             @w{const char *@var{name}}, @
             @w{const char *@var{value}})
 
 @since{1.7.0}
 
 Some minor properties of the context can be controlled with flags set
 by this function.  The properties are identified by the following
 values for @var{name}:
 
 @table @code
 @item "redraw"
 This flag is normally not changed by the caller because GPGME sets and
 clears it automatically: The flag is cleared before an operation and
 set if an operation noticed that the engine has launched a Pinentry.
 A Curses based application may use this information to redraw the
 screen; for example:
 
 @example
     err = gpgme_op_keylist_start (ctx, "foo@@example.org", 0);
     while (!err)
       @{
         err = gpgme_op_keylist_next (ctx, &key);
         if (err)
           break;
         show_key (key);
         gpgme_key_release (key);
       @}
     if ((s = gpgme_get_ctx_flag (ctx, "redraw")) && *s)
       redraw_screen ();
     gpgme_release (ctx);
 @end example
 
 
 @item "full-status"
 Using a @var{value} of "1" the status callback set by
 gpgme_set_status_cb returns all status lines with the exception of
 PROGRESS lines.  With the default of "0" the status callback is only
 called in certain situations.
 
 @item "raw-description"
 Setting the @var{value} to "1" returns human readable strings in a raw
 format.  For example the non breaking space characters ("~") will not
 be removed from the @code{description} field of the
 @code{gpgme_tofu_info_t} object.
 
 @item "export-session-key"
 Using a @var{value} of "1" specifies that the context should try to
 export the symmetric session key when decrypting data.  By default, or
 when using an empty string or "0" for @var{value}, session keys are
 not exported.
 
 @item "override-session-key"
 The string given in @var{value} is passed to the GnuPG engine to override
 the session key for decryption.  The format of that session key is
 specific to GnuPG and can be retrieved during a decrypt operation when
 the context flag "export-session-key" is enabled.  Please be aware that
 using this feature with GnuPG < 2.1.16 will leak the session key on
 many platforms via ps(1).
 
 @item "auto-key-retrieve"
 Setting the @var{value} to "1" asks the backend to automatically
 retrieve a key for signature verification if possible.  Note that this
 option makes a "web bug" like behavior possible.  Keyserver or Web Key
 Directory operators can see which keys you request, so by sending you
 a message signed by a brand new key (which you naturally will not have
 on your local keyring), the operator can tell both your IP address and
 the time when you verified the signature.
 
 @item "auto-key-import"
 Setting the @var{value} to "1" forces the GPG backend to automatically
 import a missing key for signature verification from the signature.
 
 @item "include-key-block"
 Setting the @var{value} to "1" forces the GPG backend to embed the
 signing key as well as an encryption subkey into the the signature.
 
 @item "request-origin"
 The string given in @var{value} is passed to the GnuPG engines to
 request restrictions based on the origin of the request.  Valid values
 are documented in the GnuPG manual and the gpg man page under the
 option @option{--request-origin}.  Requires at least GnuPG 2.2.6 to have an
 effect.
 
 @item "no-symkey-cache"
 For OpenPGP disable the passphrase cache used for symmetrical en- and
 decryption.  This cache is based on the message specific salt value.
 Requires at least GnuPG 2.2.7 to have an effect.
 
 @item "ignore-mdc-error"
 This flag passes the option @option{--ignore-mdc-error} to gpg.  This
 can be used to force decryption of a message which failed due to a
 missing integrity check.  This flag must be used with great caution
 and only if it is a known non-corrupted old message and the decryption
 result of the former try had the decryption result flag
 @code{legacy_cipher_nomdc} set.  For failsafe reasons this flag is
 reset after each operation.
 
 @item "auto-key-locate"
 The string given in @var{value} is passed to gpg.  This can be used
 to change the behavior of a @code{GPGME_KEYLIST_MODE_LOCATE} keylisting.
 Valid values are documented in the GnuPG manual and the gpg man page under
 the option @option{--auto-key-locate}.
 Requires at least GnuPG 2.1.18.
 
 Note: Keys retrieved through @code{auto-key-locate} are automatically
 imported in the keyring.
 
 @item trust-model
 @since{1.11.2}
 
 Change the trust-model for all GnuPG engine operations.  An empty
 string sets the trust-model back to the users default.  If the
 trust-model is not supported by GnuPG the behavior is undefined
 and will likely cause all operations to fail.  Example: "tofu+pgp".
 
 This options should be used carefully with a strict version
 requirement.  In some versions of GnuPG setting the
 trust-model changes the default trust-model for future operations.
 A change in the trust-model also can have unintended side effects, like
 rebuilding the trust-db.
 
 @item "extended-edit"
 This flag passes the option @option{--expert} to gpg key edit.  This
 can be used to get additional callbacks in @code{gpgme_op_edit}.
 
 @end table
 
 This function returns @code{0} on success.
 @end deftypefun
 
 
 @deftypefun {const char *} gpgme_get_ctx_flag  @
             (@w{gpgme_ctx_t @var{ctx}}, @
             @w{const char *@var{name}})
 
 @since{1.8.0}
 
 The value of flags settable by @code{gpgme_set_ctx_flag} can be
 retrieved by this function.  If @var{name} is unknown the function
 returns @code{NULL}.  For boolean flags an empty string is returned
 for False and the string "1" is returned for True; either atoi(3) or a
 test for an empty string can be used to get the boolean value.
 
 @end deftypefun
 
 
 @node Locale
 @subsection Locale
 @cindex locale, default
 @cindex locale, of a context
 
 A locale setting can be associated with a context.  This locale is
 passed to the crypto engine, and used for applications like the PIN
 entry, which is displayed to the user when entering a passphrase is
 required.
 
 The default locale is used to initialize the locale setting of all
 contexts created afterwards.
 
 @deftypefun gpgme_error_t gpgme_set_locale (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{category}}, @w{const char *@var{value}})
 @since{0.4.3}
 
 The function @code{gpgme_set_locale} sets the locale of the context
 @var{ctx}, or the default locale if @var{ctx} is a null pointer.
 
 The locale settings that should be changed are specified by
 @var{category}.  Supported categories are @code{LC_CTYPE},
 @code{LC_MESSAGES}, and @code{LC_ALL}, which is a wildcard you can use
 if you want to change all the categories at once.
 
 The value to be used for the locale setting is @var{value}, which will
 be copied to @acronym{GPGME}'s internal data structures.  @var{value}
 can be a null pointer, which disables setting the locale, and will
 make PIN entry and other applications use their default setting, which
 is usually not what you want.
 
 Note that the settings are only used if the application runs on a text
 terminal, and that the settings should fit the configuration of the
 output terminal.  Normally, it is sufficient to initialize the default
 value at startup.
 
 The function returns an error if not enough memory is available.
 @end deftypefun
 
 
 @node Additional Logs
 @subsection Additional Logs
 @cindex auditlog, of the engine
 @cindex auditlog
 
 Additional logs can be associated with a context.  These logs are
 engine specific and can be be obtained with @code{gpgme_op_getauditlog}.
 
 @deftypefun gpgme_error_t gpgme_op_getauditlog @
             (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{output}}, @
             @w{unsigned int @var{flags}})
 @since{1.1.1}
 
 The function @code{gpgme_op_getauditlog} is used to obtain additional
 logs as specified by @var{flags} into the @var{output} data.  If
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if a
 log could be queried from the engine, and @code{GPG_ERR_NOT_IMPLEMENTED}
 if the log specified in @var{flags} is not available for this engine.
 If no log is available @code{GPG_ERR_NO_DATA} is returned.
 
 The value in @var{flags} is a bitwise-or combination of one or
 multiple of the following bit values:
 
 @table @code
 @item GPGME_AUDITLOG_DIAG
 @since{1.11.2}
 
 Obtain diagnostic output which would be written to @code{stderr} in
 interactive use of the engine.  This can be used to provide additional
 diagnostic information in case of errors in other operations.
 
 Note: If log-file has been set in the configuration the log will
 be empty and @code{GPG_ERR_NO_DATA} will be returned.
 
 Implemented for: @code{GPGME_PROTOCOL_OpenPGP}
 
 @item GPGME_AUDITLOG_DEFAULT
 @since{1.11.2}
 
 This flag has the value 0 for compatibility reasons.  Obtains additional
 information from the engine by issuing the @code{GETAUDITLOG} command.
 For @code{GPGME_PROTOCOL_CMS} this provides additional information about
 the X509 certificate chain.
 
 Implemented for: @code{GPGME_PROTOCOL_CMS}
 
 @item GPGME_AUDITLOG_HTML
 @since{1.1.1}
 
 Same as @code{GPGME_AUDITLOG_DEFAULT} but in HTML.
 
 Implemented for: @code{GPGME_PROTOCOL_CMS}
 @end table
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_getauditlog_start @
             (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{output}}, @
             @w{unsigned int @var{flags}})
 @since{1.1.1}
 
 This is the asynchronous variant of @code{gpgme_op_getauditlog}.
 @end deftypefun
 
 @node Key Management
 @section Key Management
 @cindex key management
 
 Some of the cryptographic operations require that recipients or
 signers are specified.  This is always done by specifying the
 respective keys that should be used for the operation.  The following
 section describes how such keys can be selected and manipulated.
 
 
 @menu
 * Key objects::                   Description of the key structures.
 * Listing Keys::                  Browsing the list of available keys.
 * Information About Keys::        Requesting detailed information about keys.
 * Manipulating Keys::             Operations on keys.
 * Generating Keys::               Creating new key pairs.
 * Signing Keys::                  Adding key signatures to public keys.
 * Exporting Keys::                Retrieving key data from the key ring.
 * Importing Keys::                Adding keys to the key ring.
 * Deleting Keys::                 Removing keys from the key ring.
 * Changing Passphrases::          Change the passphrase of a key.
 * Changing TOFU Data::            Changing data pertaining to TOFU.
 * Advanced Key Editing::          Advanced key edit operation.
 @end menu
 
 @node Key objects
 @subsection Key objects
 
 The keys are represented in GPGME by structures which may only be read
 by the application but never be allocated or changed.  They are valid
 as long as the key object itself is valid.
 
 @deftp {Data type} gpgme_key_t
 
 The @code{gpgme_key_t} type is a pointer to a key object.  It has the
 following members:
 
 @table @code
 @item gpgme_keylist_mode_t keylist_mode
 @since{0.9.0}
 
 The keylist mode that was active when the key was retrieved.
 
 @item unsigned int revoked : 1
 This is true if the key is revoked.
 
 @item unsigned int expired : 1
 This is true if the key is expired.
 
 @item unsigned int disabled : 1
 This is true if the key is disabled.
 
 @item unsigned int invalid : 1
 This is true if the key is invalid. This might have several reasons,
 for a example for the S/MIME backend, it will be set during key
 listings if the key could not be validated due to missing
 certificates or unmatched policies.
 
 @item unsigned int can_encrypt : 1
 This is true if the key (ie one of its subkeys) can be used for
 encryption.
 
 @item unsigned int can_sign : 1
 This is true if the key (ie one of its subkeys) can be used to create
 data signatures.
 
 @item unsigned int can_certify : 1
 This is true if the key (ie one of its subkeys) can be used to create
 key certificates.
 
 @item unsigned int can_authenticate : 1
 @since{0.4.5}
 
 This is true if the key (ie one of its subkeys) can be used for
 authentication.
 
 @item unsigned int is_qualified : 1
 @since{1.1.0}
 
 This is true if the key can be used for qualified signatures according
 to local government regulations.
 
 @item unsigned int secret : 1
 This is true if the key is a secret key.  Note, that this will always
 be true even if the corresponding subkey flag may be false
 (offline/stub keys).  This is only set if a listing of secret keys has
 been requested or if @code{GPGME_KEYLIST_MODE_WITH_SECRET} is active.
 
 @item unsigned int origin : 5
 @since{1.8.0}
 
 Reserved for the origin of this key.
 
 @item gpgme_protocol_t protocol
 This is the protocol supported by this key.
 
 @item char *issuer_serial
 If @code{protocol} is @code{GPGME_PROTOCOL_CMS}, then this is the
 issuer serial.
 
 @item char *issuer_name
 If @code{protocol} is @code{GPGME_PROTOCOL_CMS}, then this is the
 issuer name.
 
 @item char *chain_id
 If @code{protocol} is @code{GPGME_PROTOCOL_CMS}, then this is the
 chain ID, which can be used to built the certificate chain.
 
 @item gpgme_validity_t owner_trust
 If @code{protocol} is @code{GPGME_PROTOCOL_OpenPGP}, then this is the
 owner trust.
 
 @item gpgme_subkey_t subkeys
 This is a linked list with the subkeys of the key.  The first subkey
 in the list is the primary key and usually available.
 
 @item gpgme_user_id_t uids
 This is a linked list with the user IDs of the key.  The first user ID
 in the list is the main (or primary) user ID.
 
 @item char *fpr
 @since{1.7.0}
 
 This field gives the fingerprint of the primary key.  Note that
 this is a copy of the fingerprint of the first subkey.  For an
 incomplete key (for example from a verification result) a subkey may
 be missing but this field may be set nevertheless.
 
 @item unsigned long last_update
 @since{1.8.0}
 
 Reserved for the time of the last update of this key.
 
 @end table
 @end deftp
 
 
 @deftp {Data type} gpgme_subkey_t
 @since{1.5.0}
 
 The @code{gpgme_subkey_t} type is a pointer to a subkey structure.
 Subkeys are one component of a @code{gpgme_key_t} object.  In fact,
 subkeys are those parts that contains the real information about the
 individual cryptographic keys that belong to the same key object.  One
 @code{gpgme_key_t} can contain several subkeys.  The first subkey in
 the linked list is also called the primary key.
 
 The subkey structure has the following members:
 
 @table @code
 @item gpgme_subkey_t next
 This is a pointer to the next subkey structure in the linked list, or
 @code{NULL} if this is the last element.
 
 @item unsigned int revoked : 1
 This is true if the subkey is revoked.
 
 @item unsigned int expired : 1
 This is true if the subkey is expired.
 
 @item unsigned int disabled : 1
 This is true if the subkey is disabled.
 
 @item unsigned int invalid : 1
 This is true if the subkey is invalid.
 
 @item unsigned int can_encrypt : 1
 This is true if the subkey can be used for encryption.
 
 @item unsigned int can_sign : 1
 This is true if the subkey can be used to create data signatures.
 
 @item unsigned int can_certify : 1
 This is true if the subkey can be used to create key certificates.
 
 @item unsigned int can_authenticate : 1
 @since{0.4.5}
 
 This is true if the subkey can be used for authentication.
 
 @item unsigned int is_qualified : 1
 @since{1.1.0}
 
 This is true if the subkey can be used for qualified signatures
 according to local government regulations.
 
 @item unsigned int is_de_vs : 1
 @since{1.8.0}
 
 This is true if the subkey complies with the rules for classified
 information in Germany at the restricted level (VS-NfD).  This are
 currently RSA keys of at least 2048 bits or ECDH/ECDSA keys using a
 Brainpool curve.
 
 @item unsigned int secret : 1
 This is true if the subkey is a secret key.  Note that it will be
 false if the key is actually a stub key; i.e. a secret key operation
 is currently not possible (offline-key).  This is only set if a
 listing of secret keys has been requested or if
 @code{GPGME_KEYLIST_MODE_WITH_SECRET} is active.
 
 @item gpgme_pubkey_algo_t pubkey_algo
 This is the public key algorithm supported by this subkey.
 
 @item unsigned int length
 This is the length of the subkey (in bits).
 
 @item char *keyid
 This is the key ID of the subkey in hexadecimal digits.
 
 @item char *fpr
 This is the fingerprint of the subkey in hexadecimal digits, if
 available.
 
 @item char *keygrip
 @since{1.7.0}
 
 The keygrip of the subkey in hex digit form or @code{NULL} if not
 available.
 
 @item long int timestamp
 This is the creation timestamp of the subkey.  This is -1 if the
 timestamp is invalid, and 0 if it is not available.
 
 @item long int expires
 This is the expiration timestamp of the subkey, or 0 if the subkey
 does not expire.
 
 @item unsigned int is_cardkey : 1
 @since{1.2.0}
 
 True if the secret key is stored on a smart card.
 
 @item char *card_number
 @since{1.2.0}
 
 The serial number of a smart card holding this key or @code{NULL}.
 
 @item char *curve
 For ECC algorithms the name of the curve.
 
 @end table
 @end deftp
 
 @deftp {Data type} gpgme_user_id_t
 
 A user ID is a component of a @code{gpgme_key_t} object.  One key can
 have many user IDs.  The first one in the list is the main (or
 primary) user ID.
 
 The user ID structure has the following members.
 
 @table @code
 @item gpgme_user_id_t next
 This is a pointer to the next user ID structure in the linked list, or
 @code{NULL} if this is the last element.
 
 @item unsigned int revoked : 1
 This is true if the user ID is revoked.
 
 @item unsigned int invalid : 1
 This is true if the user ID is invalid.
 
 @item gpgme_validity_t validity
 This specifies the validity of the user ID.
 
 @item char *uid
 This is the user ID string.
 
 @item char *name
 This is the name component of @code{uid}, if available.
 
 @item char *comment
 This is the comment component of @code{uid}, if available.
 
 @item char *email
 This is the email component of @code{uid}, if available.
 
 @item char *address;
 The mail address (addr-spec from RFC-5322) of the user ID string.
 This is general the same as the @code{email} part of this structure
 but might be slightly different.  If no mail address is available
 @code{NULL} is stored.
 
 @item gpgme_tofu_info_t tofu
 @since{1.7.0}
 
 If not @code{NULL} information from the TOFU database pertaining to
 this user id.
 
 @item gpgme_key_sig_t signatures
 This is a linked list with the signatures on this user ID.
 
 @item unsigned int origin : 5
 @since{1.8.0}
 
 Reserved for the origin of this user ID.
 
 @item unsigned long last_update
 @since{1.8.0}
 
 Reserved for the time of the last update of this user ID.
 
 @item char *uidhash;
 A string used by gpg to identify a user ID.  This string can be used
 at certain prompts of @code{gpgme_op_edit} to select a user ID.  Users
 must be prepared to see a @code{NULL} value here.  The format of the
 value is not specified and may depend on the GPGME or GnuPG version.
 
 @end table
 @end deftp
 
 
 @deftp {Data type} gpgme_tofu_info_t
 
 @since{1.7.0}
 
 The @code{gpgme_tofu_info_t} type is a pointer to a tofu info
 structure.  Tofu info structures are one component of a
 @code{gpgme_user_id_t} object, and provide information from the TOFU
 database pertaining to the user ID.
 
 The tofu info structure has the following members:
 
 @table @code
 @item gpgme_key_sig_t next
 This is a pointer to the next tofu info structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item unsigned int validity : 3
 This is the TOFU validity.  It can have the following values:
 
 @table @code
 @item 0
 The value @code{0} indicates a conflict.
 
 @item 1
 The value @code{1} indicates a key without history.
 
 @item 2
 The value @code{2} indicates a key with too little history.
 
 @item 3
 The value @code{3} indicates a key with enough history for basic trust.
 
 @item 4
 The value @code{4} indicates a key with a lot of history.
 
 @end table
 
 @item unsigned int policy : 4
 This is the TOFU policy, see @code{gpgme_tofu_policy_t}.
 
 @item unsigned short signcount
 This is the number of signatures seen for this binding (or
 @code{USHRT_MAX} if there are more than that).
 
 @item unsigned short encrcount
 This is the number of encryptions done with this binding (or
 @code{USHRT_MAX} if there are more than that).
 
 @item unsigned long signfirst
 Number of seconds since Epoch when the first signature was seen with
 this binding.
 
 @item unsigned long signlast
 Number of seconds since Epoch when the last signature was seen with
 this binding.
 
 @item unsigned long encrfirst
 Number of seconds since Epoch when the first encryption was done with
 this binding.
 
 @item unsigned long encrlast
 Number of seconds since Epoch when the last encryption was done with
 this binding.
 
 @item char *description
 A human-readable string summarizing the TOFU data (or NULL).
 
 @end table
 @end deftp
 
 
 @deftp {Data type} gpgme_key_sig_t
 
 The @code{gpgme_key_sig_t} type is a pointer to a key signature structure.
 Key signatures are one component of a @code{gpgme_key_t} object, and
 validate user IDs on the key in the OpenPGP protocol.
 
 The signatures on a key are only available if the key was retrieved
 via a listing operation with the @code{GPGME_KEYLIST_MODE_SIGS} mode
 enabled, because it can be expensive to retrieve all signatures of a
 key.
 
 The signature notations on a key signature are only available if the
 key was retrieved via a listing operation with the
 @code{GPGME_KEYLIST_MODE_SIG_NOTATIONS} mode enabled, because it can
 be expensive to retrieve all signature notations.
 
 The key signature structure has the following members:
 
 @table @code
 @item gpgme_key_sig_t next
 This is a pointer to the next key signature structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item unsigned int revoked : 1
 This is true if the key signature is a revocation signature.
 
 @item unsigned int expired : 1
 This is true if the key signature is expired.
 
 @item unsigned int invalid : 1
 This is true if the key signature is invalid.
 
 @item unsigned int exportable : 1
 This is true if the key signature is exportable.
 
+@item unsigned int trust_depth : 8
+This is the depth of a trust signature, or 0 if the key signature is not
+a trust signature.
+
+@item unsigned int trust_value : 8
+This is the trust amount of a trust signature.
+
 @item gpgme_pubkey_algo_t pubkey_algo
 This is the public key algorithm used to create the signature.
 
 @item char *keyid
 This is the key ID of the key (in hexadecimal digits) used to create
 the signature.
 
 @item long int timestamp
 This is the creation timestamp of the key signature.  This is -1 if
 the timestamp is invalid, and 0 if it is not available.
 
 @item long int expires
 This is the expiration timestamp of the key signature, or 0 if the key
 signature does not expire.
 
+@item char *trust_scope
+This is a regular expression that limits the scope of a trust signature.
+Users must be prepared to see a @code{NULL} value here.
+
 @item gpgme_error_t status
 This is the status of the signature and has the same meaning as the
 member of the same name in a @code{gpgme_signature_t} object.
 
 @item unsigned int sig_class
 This specifies the signature class of the key signature.  The meaning
 is specific to the crypto engine.
 
 @item char *uid
 This is the main user ID of the key used to create the signature.
 
 @item char *name
 This is the name component of @code{uid}, if available.
 
 @item char *comment
 This is the comment component of @code{uid}, if available.
 
 @item char *email
 This is the email component of @code{uid}, if available.
 
 @item gpgme_sig_notation_t notations
 This is a linked list with the notation data and policy URLs.
 @end table
 @end deftp
 
 
 
 @node Listing Keys
 @subsection Listing Keys
 @cindex listing keys
 @cindex key listing
 @cindex key listing, start
 @cindex key ring, list
 @cindex key ring, search
 
 @deftypefun gpgme_error_t gpgme_op_keylist_start (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}}, @w{int @var{secret_only}})
 
 The function @code{gpgme_op_keylist_start} initiates a key listing
 operation inside the context @var{ctx}.  It sets everything up so that
 subsequent invocations of @code{gpgme_op_keylist_next} return the keys
 in the list.
 
 If @var{pattern} is @code{NULL}, all available keys are returned.
 Otherwise, @var{pattern} contains an engine specific expression that
 is used to limit the list to all keys matching the pattern.  Note that
 the total length of the pattern is restricted to an engine-specific
 maximum (a couple of hundred characters are usually accepted).  The
 pattern should be used to restrict the search to a certain common name
 or user, not to list many specific keys at once by listing their
 fingerprints or key IDs.
 
 If @var{secret_only} is not @code{0}, the list is restricted to secret
 keys only.
 
 The context will be busy until either all keys are received (and
 @code{gpgme_op_keylist_next} returns @code{GPG_ERR_EOF}), or
 @code{gpgme_op_keylist_end} is called to finish the operation.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_keylist_ext_start (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}[]}, @w{int @var{secret_only}}, @w{int @var{reserved}})
 
 The function @code{gpgme_op_keylist_ext_start} initiates an extended
 key listing operation inside the context @var{ctx}.  It sets
 everything up so that subsequent invocations of
 @code{gpgme_op_keylist_next} return the keys in the list.
 
 If @var{pattern} or @var{*pattern} is @code{NULL}, all available keys
 are returned.  Otherwise, @var{pattern} is a @code{NULL} terminated
 array of strings that are used to limit the list to all keys matching
 at least one of the patterns verbatim.  Note that the total length of
 all patterns is restricted to an engine-specific maximum (the exact
 limit also depends on the number of patterns and amount of quoting
 required, but a couple of hundred characters are usually accepted).
 Patterns should be used to restrict the search to a certain common
 name or user, not to list many specific keys at once by listing their
 fingerprints or key IDs.
 
 If @var{secret_only} is not @code{0}, the list is restricted to secret
 keys only.
 
 The value of @var{reserved} must be @code{0}.
 
 The context will be busy until either all keys are received (and
 @code{gpgme_op_keylist_next} returns @code{GPG_ERR_EOF}), or
 @code{gpgme_op_keylist_end} is called to finish the operation.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_keylist_from_data_start @
             (@w{gpgme_ctx_t @var{ctx}}, @
              @w{gpgme_data_t @var{data}}, @
              @w{int @var{reserved}})
 
 @since{1.8.0}
 
 The function @code{gpgme_op_keylist_from_data_start} initiates a key
 listing operation inside the context @var{ctx}.  In contrast to the
 other key listing operation the keys are read from the supplied
 @var{data} and not from the local key database.  The keys are also not
 imported into the local key database.  The function sets everything up
 so that subsequent invocations of @code{gpgme_op_keylist_next} return
 the keys from @var{data}.
 
 The value of @var{reserved} must be @code{0}.
 
 This function requires at least GnuPG version 2.1.14 and currently
 works only with OpenPGP keys.
 
 The context will be busy until either all keys are received (and
 @code{gpgme_op_keylist_next} returns @code{GPG_ERR_EOF}), or
 @code{gpgme_op_keylist_end} is called to finish the operation.
 While the context is busy @var{data} may not be released.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_keylist_next (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t *@var{r_key}})
 
 The function @code{gpgme_op_keylist_next} returns the next key in the
 list created by a previous @code{gpgme_op_keylist_start} operation in
 the context @var{ctx}.  The key will have one reference for the user.
 @xref{Manipulating Keys}.
 
 This is the only way to get at @code{gpgme_key_t} objects in
 @acronym{GPGME}.
 
 If the last key in the list has already been returned,
 @code{gpgme_op_keylist_next} returns @code{GPG_ERR_EOF}.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{r_key} is not a valid pointer, and
 @code{GPG_ERR_ENOMEM} if there is not enough memory for the operation.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_keylist_end (@w{gpgme_ctx_t @var{ctx}})
 
 The function @code{gpgme_op_keylist_end} ends a pending key list
 operation in the context @var{ctx}.
 
 After the operation completed successfully, the result of the key
 listing operation can be retrieved with
 @code{gpgme_op_keylist_result}.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, and @code{GPG_ERR_ENOMEM} if at some
 time during the operation there was not enough memory available.
 @end deftypefun
 
 The following example illustrates how all keys containing a certain
 string (@code{g10code}) can be listed with their key ID and the name
 and email address of the main user ID:
 
 @example
 gpgme_ctx_t ctx;
 gpgme_key_t key;
 gpgme_error_t err = gpgme_new (&ctx);
 
 if (!err)
   @{
     err = gpgme_op_keylist_start (ctx, "g10code", 0);
     while (!err)
       @{
         err = gpgme_op_keylist_next (ctx, &key);
         if (err)
           break;
         printf ("%s:", key->subkeys->keyid);
         if (key->uids && key->uids->name)
           printf (" %s", key->uids->name);
         if (key->uids && key->uids->email)
           printf (" <%s>", key->uids->email);
         putchar ('\n');
         gpgme_key_release (key);
       @}
     gpgme_release (ctx);
   @}
 if (gpg_err_code (err) != GPG_ERR_EOF)
   @{
     fprintf (stderr, "can not list keys: %s\n", gpgme_strerror (err));
     exit (1);
   @}
 @end example
 
 @deftp {Data type} {gpgme_keylist_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_keylist_*} operation.  After successfully ending a key
 listing operation, you can retrieve the pointer to the result with
 @code{gpgme_op_keylist_result}.  The structure contains the following
 member:
 
 @table @code
 @item unsigned int truncated : 1
 This is true if the crypto backend had to truncate the result, and
 less than the desired keys could be listed.
 @end table
 @end deftp
 
 @deftypefun gpgme_keylist_result_t gpgme_op_keylist_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_keylist_result} returns a
 @code{gpgme_keylist_result_t} pointer to a structure holding the
 result of a @code{gpgme_op_keylist_*} operation.  The pointer is only
 valid if the last operation on the context was a key listing
 operation, and if this operation finished successfully.  The returned
 pointer is only valid until the next operation is started on the
 context.
 @end deftypefun
 
 In a simple program, for which a blocking operation is acceptable, the
 following function can be used to retrieve a single key.
 
 @deftypefun gpgme_error_t gpgme_get_key (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{fpr}}, @w{gpgme_key_t *@var{r_key}}, @w{int @var{secret}})
 The function @code{gpgme_get_key} gets the key with the fingerprint
 (or key ID) @var{fpr} from the crypto backend and return it in
 @var{r_key}.  If @var{secret} is true, get the secret key.  The
 currently active keylist mode is used to retrieve the key.  The key
 will have one reference for the user.
 
 If the key is not found in the keyring, @code{gpgme_get_key} returns
 the error code @code{GPG_ERR_EOF} and *@var{r_key} will be set to
 @code{NULL}.
 
 The function returns the error code @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{r_key} is not a valid pointer or @var{fpr} is not a
 fingerprint or key ID, @code{GPG_ERR_AMBIGUOUS_NAME} if the key ID was
 not a unique specifier for a key, and @code{GPG_ERR_ENOMEM} if at some
 time during the operation there was not enough memory available.
 @end deftypefun
 
 
 @node Information About Keys
 @subsection Information About Keys
 @cindex key, information about
 @cindex key, attributes
 @cindex attributes, of a key
 
 Please see the beginning of this section for more information about
 @code{gpgme_key_t} objects.
 
 @deftp {Data type} gpgme_validity_t
 The @code{gpgme_validity_t} type is used to specify the validity of a user ID
 in a key.  The following validities are defined:
 
 @table @code
 @item GPGME_VALIDITY_UNKNOWN
 The user ID is of unknown validity.  The string representation of this
 validity is ``?''.
 
 @item GPGME_VALIDITY_UNDEFINED
 The validity of the user ID is undefined.  The string representation of this
 validity is ``q''.
 
 @item GPGME_VALIDITY_NEVER
 The user ID is never valid.  The string representation of this
 validity is ``n''.
 
 @item GPGME_VALIDITY_MARGINAL
 The user ID is marginally valid.  The string representation of this
 validity is ``m''.
 
 @item GPGME_VALIDITY_FULL
 The user ID is fully valid.  The string representation of this
 validity is ``f''.
 
 @item GPGME_VALIDITY_ULTIMATE
 The user ID is ultimately valid.  The string representation of this
 validity is ``u''.
 @end table
 @end deftp
 
 
 
 
 @node Manipulating Keys
 @subsection Manipulating Keys
 @cindex key, manipulation
 
 @deftypefun void gpgme_key_ref (@w{gpgme_key_t @var{key}})
 The function @code{gpgme_key_ref} acquires an additional reference for
 the key @var{key}.
 @end deftypefun
 
 @deftypefun void gpgme_key_unref (@w{gpgme_key_t @var{key}})
 The function @code{gpgme_key_unref} releases a reference for the key
 @var{key}.  If this was the last reference, the key will be destroyed
 and all resources associated to it will be released.
 @end deftypefun
 
 @c
 @c  gpgme_op_setexpire
 @c
 @deftypefun gpgme_error_t gpgme_op_setexpire @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{unsigned long @var{expires}}, @
        @w{const char *@var{subfprs}}, @
        @w{unsigned int @var{reserved}});
 
 @since{1.14.1}
 
 The function @code{gpgme_op_setexpire} sets the expiration time of
 the key @var{key} or of the specified subkeys.
 This function requires at least version 2.1.22 of GnuPG.
 
 @var{key} specifies the key to operate on.
 
 @var{expires} specifies the expiration time in seconds from now.
 To be similar to other usages where expiration times are provided
 in unsigned long this is similar to the key creation date
 and so it is in seconds from NOW.
 
 The common case is to use 0 to not set an expiration time.
 Note that this parameter takes an unsigned long value and not
 a @code{time_t} to avoid problems on systems which use a signed
 32 bit @code{time_t}.  Note further that the OpenPGP protocol
 uses 32 bit values for timestamps and thus can
 only encode dates up to the year 2106.
 
 @var{subfprs} selects the subkey(s) for which the expiration time
 should be set.  If @var{subfprs} is set to @code{NULL}, then the
 expiration time of the primary key is set.  If @var{subfprs} is
 an asterisk (@code{*}), then the expiration times of all non-revoked
 and not yet expired subkeys are set.  To select more than one subkey
 put all subkey fingerprints into one string separated by linefeeds
 characters (@code{\n}).
 
 @var{reserved} is reserved for later use and must be @code{0}.
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_setexpire_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{unsigned long @var{expires}}, @
        @w{const char *@var{subfprs}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.14.1}
 
 The function @code{gpgme_op_setexpire_start} initiates a
 @code{gpgme_op_setexpire} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_revuid_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.14.1}
 
 The function @code{gpgme_op_setexpire_start} initiates a
 @code{gpgme_op_setexpire} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @node Generating Keys
 @subsection Generating Keys
 @cindex key, creation
 @cindex key ring, add
 
 GPGME provides a set of functions to create public key pairs.  Most of
 these functions require the use of GnuPG 2.1 and later; for older
 GnuPG versions the @code{gpgme_op_genkey} function can be used.
 Existing code which wants to update to the new functions or new code
 which shall supports older GnuPG versions may try the new functions
 first and provide a fallback to the old function if the error code
 @code{GPG_ERR_NOT_SUPPORTED} is received.
 
 @c
 @c  gpgme_op_createkey
 @c
 @deftypefun gpgme_error_t gpgme_op_createkey @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{const char *@var{userid}}, @
        @w{const char *@var{algo}}, @
        @w{unsigned long @var{reserved}}, @
        @w{unsigned long @var{expires}}, @
        @w{gpgme_key_t @var{extrakey}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_createkey} generates a new key for the
 procotol active in the context @var{ctx}.  As of now this function
 does only work for OpenPGP and requires at least version 2.1.13 of
 GnuPG.
 
 @var{userid} is commonly the mail address associated with the key.
 GPGME does not require a specific syntax but if more than a mail
 address is given, RFC-822 style format is suggested.  The value is
 expected to be in UTF-8 encoding (i.e. no IDN encoding for mail
 addresses).  This is a required parameter.
 
 @var{algo} specifies the algorithm for the new key (actually a keypair
 of public and private key).  For a list of supported algorithms, see
 the GnuPG manual.  If @var{algo} is @code{NULL} or the string
 "default", the key is generated using the default algorithm of the
 engine.  If the string "future-default" is used the engine may use an
 algorithm which is planned to be the default in a future release of
 the engine; however existing implementation of the protocol may not be
 able to already handle such future algorithms.  For the OpenPGP
 protocol, the specification of a default algorithm, without requesting
 a non-default usage via @var{flags}, triggers the creation of a
 primary key plus a secondary key (subkey).
 
 @var{reserved} must be set to zero.
 
 @var{expires} specifies the expiration time in seconds.  If you supply
 0, a reasonable expiration time is chosen.  Use the flag
 @code{GPGME_CREATE_NOEXPIRE} to create keys that do not expire.  Note
 that this parameter takes an unsigned long value and not a
 @code{time_t} to avoid problems on systems which use a signed 32 bit
 @code{time_t}.  Note further that the OpenPGP protocol uses 32 bit
 values for timestamps and thus can only encode dates up to the year
 2106.
 
 @var{extrakey} is currently not used and must be set to @code{NULL}.
 A future version of GPGME may use this parameter to create X.509 keys.
 
 @var{flags} can be set to the bit-wise OR of the following flags:
 
 @table @code
 @item GPGME_CREATE_SIGN
 @itemx GPGME_CREATE_ENCR
 @itemx GPGME_CREATE_CERT
 @itemx GPGME_CREATE_AUTH
 @since{1.7.0}
 
 Do not create the key with the default capabilities (key usage) of the
 requested algorithm but use those explicitly given by these flags:
 ``signing'', ``encryption'', ``certification'', or ``authentication''.
 The allowed combinations depend on the algorithm.
 
 If any of these flags are set and a default algorithm has been
 selected only one key is created in the case of the OpenPGP
 protocol.
 
 @item GPGME_CREATE_NOPASSWD
 @since{1.7.0}
 
 Request generation of the key without password protection.
 
 @item GPGME_CREATE_SELFSIGNED
 @since{1.7.0}
 
 For an X.509 key do not create a CSR but a self-signed certificate.
 This has not yet been implemented.
 
 @item GPGME_CREATE_NOSTORE
 @since{1.7.0}
 
 Do not store the created key in the local key database.
 This has not yet been implemented.
 
 @item GPGME_CREATE_WANTPUB
 @itemx GPGME_CREATE_WANTSEC
 @since{1.7.0}
 
 Return the public or secret key as part of the result structure.
 This has not yet been implemented.
 
 @item GPGME_CREATE_FORCE
 @since{1.7.0}
 
 The engine does not allow the creation of a key with a user ID
 already existing in the local key database.  This flag can be used to
 override this check.
 
 @item GPGME_CREATE_NOEXPIRE
 @since{1.9.0}
 
 Request generation of keys that do not expire.
 
 @end table
 
 After the operation completed successfully, information about the
 created key can be retrieved with @code{gpgme_op_genkey_result}.
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_createkey_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{const char *@var{userid}}, @
        @w{const char *@var{algo}}, @
        @w{unsigned long @var{reserved}}, @
        @w{unsigned long @var{expires}}, @
        @w{gpgme_key_t @var{extrakey}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_createkey_start} initiates a
 @code{gpgme_op_createkey} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 @c
 @c  gpgme_op_createsubkey
 @c
 @deftypefun gpgme_error_t gpgme_op_createsubkey @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{algo}}, @
        @w{unsigned long @var{reserved}}, @
        @w{unsigned long @var{expires}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_createsubkey} creates and adds a new
 subkey to the primary OpenPGP key given by @var{KEY}.  The only
 allowed protocol in @var{ctx} is @code{GPGME_PROTOCOL_OPENPGP}.
 Subkeys (aka secondary keys) are a concept in the OpenPGP protocol to
 bind several keys to a primary key.  As of now this function requires
 at least version 2.1.13 of GnuPG.
 
 @var{key} specifies the key to operate on.
 
 @var{algo} specifies the algorithm for the new subkey.  For a list of
 supported algorithms, see the GnuPG manual.  If @var{algo} is
 @code{NULL} or the string "default", the subkey is generated using the
 default algorithm for an encryption subkey of the engine.  If the
 string "future-default" is used the engine may use an encryption
 algorithm which is planned to be the default in a future release of
 the engine; however existing implementation of the protocol may not be
 able to already handle such future algorithms.
 
 @var{reserved} must be set to zero.
 
 @var{expires} specifies the expiration time in seconds.  If you supply
 0, a reasonable expiration time is chosen.  Use the flag
 @code{GPGME_CREATE_NOEXPIRE} to create keys that do not expire.  Note
 that this parameter takes an unsigned long value and not a
 @code{time_t} to avoid problems on systems which use a signed 32 bit
 @code{time_t}.  Note further that the OpenPGP protocol uses 32 bit
 values for timestamps and thus can only encode dates up to the year
 2106.
 
 @var{flags} takes the same values as described above for
 @code{gpgme_op_createkey}.
 
 After the operation completed successfully, information about the
 created key can be retrieved with @code{gpgme_op_genkey_result}.
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_createsubkey_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{algo}}, @
        @w{unsigned long @var{reserved}}, @
        @w{unsigned long @var{expires}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_createsubkey_start} initiates a
 @code{gpgme_op_createsubkey} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @c
 @c  gpgme_op_adduid
 @c
 @deftypefun gpgme_error_t gpgme_op_adduid @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_adduid} adds a new user ID to the OpenPGP
 key given by @var{KEY}.  Adding additional user IDs after key creation
 is a feature of the OpenPGP protocol and thus the protocol for the
 context @var{ctx} must be set to OpenPGP.  As of now this function
 requires at least version 2.1.13 of GnuPG.
 
 @var{key} specifies the key to operate on.
 
 @var{userid} is the user ID to add to the key.  A user ID is commonly
 the mail address to be associated with the key.  GPGME does not
 require a specific syntax but if more than a mail address is given,
 RFC-822 style format is suggested.  The value is expected to be in
 UTF-8 encoding (i.e. no IDN encoding for mail addresses).  This is a
 required parameter.
 
 @var{flags} are currently not used and must be set to zero.
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_adduid_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_adduid_start} initiates a
 @code{gpgme_op_adduid} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @c
 @c  gpgme_op_revuid
 @c
 @deftypefun gpgme_error_t gpgme_op_revuid @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_revuid} revokes a user ID from the OpenPGP
 key given by @var{KEY}.  Revoking user IDs after key creation is a
 feature of the OpenPGP protocol and thus the protocol for the context
 @var{ctx} must be set to OpenPGP.  As of now this function requires at
 least version 2.1.13 of GnuPG.
 
 @var{key} specifies the key to operate on.
 
 @var{userid} is the user ID to be revoked from the key.  The user ID
 must be given verbatim because the engine does an exact and case
 sensitive match.  Thus the @code{uid} field from the user ID object
 (@code{gpgme_user_id_t}) is to be used.  This is a required parameter.
 
 @var{flags} are currently not used and must be set to zero.
 
 Note that the engine won't allow to revoke the last valid user ID.  To
 change a user ID is better to first add the new user ID, then revoke
 the old one, and finally publish the key.
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_revuid_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_revuid_start} initiates a
 @code{gpgme_op_revuid} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @c
 @c  gpgme_op_set_uid_flag
 @c
 @deftypefun gpgme_error_t gpgme_op_set_ui_flag @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{cons char * @var{name}}, @
        @w{cons char * @var{value}});
 
 @since{1.8.0}
 
 The function @code{gpgme_op_set_uid_flag} is used to set flags on a
 user ID from the OpenPGP key given by @var{KEY}.  Setting flags on
 user IDs after key creation is a feature of the OpenPGP protocol and
 thus the protocol for the context @var{ctx} must be set to OpenPGP.
 
 @var{key} specifies the key to operate on.  This parameters is required.
 
 @var{userid} is the user ID of the key to be manipulated.  This user ID
 must be given verbatim because the engine does an exact and case
 sensitive match.  Thus the @code{uid} field from the user ID object
 (@code{gpgme_user_id_t}) is to be used.  This is a required parameter.
 
 @var{name} names the flag which is to be changed.  The only currently
 supported flag is:
 
 @table @code
 @item primary
 This sets the primary key flag on the given user ID.  All other
 primary key flag on other user IDs are removed.  @var{value} must be
 given as NULL.  For technical reasons this functions bumps the
 creation timestamp of all affected self-signatures up by one second.
 At least GnuPG version 2.1.20 is required.
 
 @end table
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_set_uid_flag_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{cons char * @var{name}}, @
        @w{cons char * @var{value}});
 
 @since{1.8.0}
 
 The function @code{gpgme_op_set_uid_flag_start} initiates a
 @code{gpgme_op_set_uid_flag} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 @c
 @c  gpgme_op_genkey
 @c
 @deftypefun gpgme_error_t gpgme_op_genkey @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{const char *@var{parms}}, @
        @w{gpgme_data_t @var{public}}, @
        @w{gpgme_data_t @var{secret}})
 
 The function @code{gpgme_op_genkey} generates a new key pair in the
 context @var{ctx}.  The meaning of @var{public} and @var{secret}
 depends on the crypto backend.
 
 GPG does not support @var{public} and @var{secret}, they should be
 @code{NULL}.  GnuPG will generate a key pair and add it to the
 standard key ring.  The fingerprint of the generated key is available
 with @code{gpgme_op_genkey_result}.
 
 GpgSM requires @var{public} to be a writable data object.  GpgSM will
 generate a secret key (which will be stored by @command{gpg-agent},
 and return a certificate request in @var{public}, which then needs to
 be signed by the certification authority and imported before it can be
 used.  GpgSM does not make the fingerprint available.
 
 The argument @var{parms} specifies parameters for the key in an string
 that looks something like XML.  The details about the format of
 @var{parms} are specific to the crypto engine used by @var{ctx}.  The
 first line of the parameters must be @code{<GnupgKeyParams
 format="internal">} and the last line must be
 @code{</GnupgKeyParams>}.  Every line in between the first and last
 lines is treated as a Header: Value pair.  In particular, no XML
 escaping is necessary if you need to include the characters @code{<},
 @code{>}, or @code{&}.
 
 Here is an example for GnuPG as the crypto engine (all parameters of
 OpenPGP key generation are documented in the GPG manual):
 
 @example
 <GnupgKeyParms format="internal">
 Key-Type: default
 Subkey-Type: default
 Name-Real: Joe Tester
 Name-Comment: with stupid passphrase
 Name-Email: joe@@foo.bar
 Expire-Date: 0
 Passphrase: abc
 </GnupgKeyParms>
 @end example
 
 Here is an example for GpgSM as the crypto engine (all parameters of
 OpenPGP key generation are documented in the GPGSM manual):
 
 @example
 <GnupgKeyParms format="internal">
 Key-Type: RSA
 Key-Length: 1024
 Name-DN: C=de,O=g10 code,OU=Testlab,CN=Joe 2 Tester
 Name-Email: joe@@foo.bar
 </GnupgKeyParms>
 @end example
 
 Strings should be given in UTF-8 encoding.  The only format supported
 for now is ``internal''.  The content of the @code{GnupgKeyParms}
 container is passed verbatim to the crypto backend.  Control
 statements are not allowed.
 
 After the operation completed successfully, the result can be
 retrieved with @code{gpgme_op_genkey_result}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{parms} is not a well-formed string (e.g. does not have the
 expected tag-like headers and footers), @code{GPG_ERR_NOT_SUPPORTED}
 if @var{public} or @var{secret} is not valid, and
 @code{GPG_ERR_GENERAL} if no key was created by the backend.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_genkey_start (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{parms}}, @w{gpgme_data_t @var{public}}, @w{gpgme_data_t @var{secret}})
 
 The function @code{gpgme_op_genkey_start} initiates a
 @code{gpgme_op_genkey} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{parms} is not a valid XML string, and
 @code{GPG_ERR_NOT_SUPPORTED} if @var{public} or @var{secret} is not
 @code{NULL}.
 @end deftypefun
 
 
 @c
 @c  gpgme_op_genkey_result
 @c
 @deftp {Data type} {gpgme_genkey_result_t}
 
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_genkey} operation.  After successfully generating a
 key, you can retrieve the pointer to the result with
 @code{gpgme_op_genkey_result}.  The structure contains the following
 members:
 
 @table @code
 @item unsigned int primary : 1
 This flag is set to 1 if a primary key was created and to 0
 if not.
 
 @item unsigned int sub : 1
 This flag is set to 1 if a subkey was created and to 0 if not.
 
 @item unsigned int uid : 1
 This flag is set to 1 if a user ID was created and to 0 if not.
 
 @item char *fpr
 This is the fingerprint of the key that was created.  If both a
 primary and a subkey were generated, the fingerprint of the primary
 key will be returned.  If the crypto engine does not provide the
 fingerprint, @code{fpr} will be a null pointer.
 
 @item gpgme_data_t pubkey
 @since{1.7.0}
 
 This will eventually be used to return the public key.  It is
 currently not used.
 
 @item gpgme_data_t seckey
 @since{1.7.0}
 
 This will eventually be used to return the secret key.  It is
 currently not used.
 
 @end table
 @end deftp
 
 @deftypefun gpgme_genkey_result_t gpgme_op_genkey_result (@w{gpgme_ctx_t @var{ctx}})
 
 The function @code{gpgme_op_genkey_result} returns a
 @code{gpgme_genkey_result_t} pointer to a structure holding the result of
 a @code{gpgme_op_genkey} operation.  The pointer is only valid if the
 last operation on the context was a @code{gpgme_op_genkey} or
 @code{gpgme_op_genkey_start} operation, and if this operation finished
 successfully.  The returned pointer is only valid until the next
 operation is started on the context.
 
 @end deftypefun
 
 
 @c
 @c  SIGNING KEYS
 @c
 @node Signing Keys
 @subsection Signing Keys
 @cindex key, signing
 
 Key signatures are a unique concept of the OpenPGP protocol.  They can
 be used to certify the validity of a key and are used to create the
 Web-of-Trust (WoT).  Instead of using the @code{gpgme_op_interact}
 function along with a finite state machine, GPGME provides a
 convenient function to create key signatures when using modern GnuPG
 versions.
 
 
 @c
 @c  gpgme_op_keysign
 @c
 @deftypefun gpgme_error_t gpgme_op_keysign @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned long @var{expires}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_keysign} adds a new key signature to the
 public key @var{KEY}.   This function requires at least version 2.1.12 of
 GnuPG.
 
 @var{CTX} is the usual context which describes the protocol to use
 (which must be OpenPGP) and has also the list of signer keys to be
 used for the signature.  The common case is to use the default key for
 signing other keys.  If another key or more than one key shall be used
 for a key signature, @code{gpgme_signers_add} can be used.
 @xref{Selecting Signers}.
 
 @var{key} specifies the key to operate on.
 
 @var{userid} selects the user ID or user IDs to be signed.  If
 @var{userid} is set to @code{NULL} all valid user IDs are signed.  The
 user ID must be given verbatim because the engine does an exact and
 case sensitive match.  Thus the @code{uid} field from the user ID
 object (@code{gpgme_user_id_t}) is to be used.  To select more than
 one user ID put them all into one string separated by linefeeds
 characters (@code{\n}) and set the flag @code{GPGME_KEYSIGN_LFSEP}.
 
 @var{expires} specifies the expiration time of the new signature in
 seconds.  The common case is to use 0 to not set an expiration date.
 However, if the configuration of the engine defines a default
 expiration for key signatures, that is still used unless the flag
 @code{GPGME_KEYSIGN_NOEXPIRE} is used.  Note that this parameter takes
 an unsigned long value and not a @code{time_t} to avoid problems on
 systems which use a signed 32 bit @code{time_t}.  Note further that
 the OpenPGP protocol uses 32 bit values for timestamps and thus can
 only encode dates up to the year 2106.
 
 @var{flags} can be set to the bit-wise OR of the following flags:
 
 @table @code
 @item GPGME_KEYSIGN_LOCAL
 @since{1.7.0}
 
 Instead of creating an exportable key signature, create a key
 signature which is is marked as non-exportable.
 
 @item GPGME_KEYSIGN_LFSEP
 @since{1.7.0}
 
 Although linefeeds are uncommon in user IDs this flag is required to
 explicitly declare that @var{userid} may contain several linefeed
 separated user IDs.
 
 @item GPGME_KEYSIGN_NOEXPIRE
 Force the creation of a key signature without an expiration date.  This
 overrides @var{expire} and any local configuration of the engine.
 
 @item GPGME_KEYSIGN_FORCE
 Force the creation of a new signature even if one already exists.
 This flag has an effect only if the gpg version is at least 2.2.28 but
 won't return an error with older versions.
 
 @end table
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_keysign_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned long @var{expires}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.7.0}
 
 The function @code{gpgme_op_keysign_start} initiates a
 @code{gpgme_op_keysign} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @c
 @c  gpgme_op_revsig
 @c
 @deftypefun gpgme_error_t gpgme_op_revsig @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{gpgme_key_t @var{signing_key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.14.1}
 
 The function @code{gpgme_op_revsig} revokes key signatures of the
 public key @var{key} made with the key @var{signing_key}.   This
 function requires at least version 2.2.24 of GnuPG.
 
 @var{key} specifies the key to operate on.
 
 @var{signing_key} specifies the key whose signatures shall be revoked.
 
 @var{userid} selects the user ID or user IDs whose signatures shall
 be revoked.  If @var{userid} is set to @code{NULL} the signatures
 on all user IDs are revoked.  The user ID must be given verbatim
 because the engine does an exact and case sensitive match.  Thus the
 @code{uid} field from the user ID object (@code{gpgme_user_id_t}) is to
 be used.  To select more than one user ID put them all into one string
 separated by linefeeds characters (@code{\n}) and set the flag
 @code{GPGME_REVSIG_LFSEP}.
 
 @var{flags} can be set to the bit-wise OR of the following flags:
 
 @table @code
 @item GPGME_REVSIG_LFSEP
 @since{1.14.1}
 
 Although linefeeds are uncommon in user IDs this flag is required to
 explicitly declare that @var{userid} may contain several linefeed
 separated user IDs.
 
 @end table
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_revsig_start @
       (@w{gpgme_ctx_t @var{ctx}}, @
        @w{gpgme_key_t @var{key}}, @
        @w{gpgme_key_t @var{signing_key}}, @
        @w{const char *@var{userid}}, @
        @w{unsigned int @var{flags}});
 
 @since{1.14.1}
 
 The function @code{gpgme_op_revsig_start} initiates a
 @code{gpgme_op_revsig} operation; see there for details.  It must
 be completed by calling @code{gpgme_wait} on the context.
 @xref{Waiting For Completion}.
 
 @end deftypefun
 
 
 @c
 @c  EXPORTING KEYS
 @c
 @node Exporting Keys
 @subsection Exporting Keys
 @cindex key, export
 @cindex key ring, export from
 
 Exporting keys means the same as running @command{gpg} with the command
 @option{--export}.  However, a mode flag can be used to change the way
 the export works.  The available mode flags are described below, they
 may be or-ed together.
 
 @table @code
 
 @item GPGME_EXPORT_MODE_EXTERN
 If this bit is set, the output is send directly to the default
 keyserver. This is currently only allowed for OpenPGP keys.  It is good
 practise to not send more than a few dozens key to a keyserver at one
 time.  Using this flag requires that the @var{keydata} argument of the
 export function is set to @code{NULL}.
 
 @item GPGME_EXPORT_MODE_MINIMAL
 @since{1.3.1}
 
 If this bit is set, the smallest possible key is exported.  For OpenPGP
 keys it removes all signatures except for the latest self-signatures.
 For X.509 keys it has no effect.
 
 @item GPGME_EXPORT_MODE_SSH
 @since{1.4.0}
 
 If this bit is set, the latest authentication key of the requested
 OpenPGP key is exported in the OpenSSH public key format.  This
 accepts just a single key; to force the export of a specific subkey
 a fingerprint pattern with an appended exclamation mark may be used.
 
 
 @item GPGME_EXPORT_MODE_SECRET
 @since{1.6.0}
 
 Instead of exporting the public key, the secret key is exported.  This
 may not be combined with @code{GPGME_EXPORT_MODE_EXTERN}.  For X.509
 the export format is PKCS#8.
 
 @item GPGME_EXPORT_MODE_RAW
 @since{1.6.0}
 
 If this flag is used with @code{GPGME_EXPORT_MODE_SECRET} for an X.509
 key the export format will be changed to PKCS#1.  This flag may not be
 used with OpenPGP.
 
 @item GPGME_EXPORT_MODE_PKCS12
 @since{1.6.0}
 
 If this flag is used with @code{GPGME_EXPORT_MODE_SECRET} for an X.509
 key the export format will be changed to PKCS#12 which also includes
 the certificate.  This flag may not be used with OpenPGP.
 
 @item GPGME_EXPORT_MODE_NOUID
 @since{1.12.0 - experimental}
 Do not export user ids.  Works only with certain gpg version.
 
 @end table
 
 
 
 @deftypefun gpgme_error_t gpgme_op_export (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_export} extracts public keys and returns
 them in the data buffer @var{keydata}.  The output format of the key
 data returned is determined by the @acronym{ASCII} armor attribute set
 for the context @var{ctx}, or, if that is not set, by the encoding
 specified for @var{keydata}.
 
 If @var{pattern} is @code{NULL}, all available keys are returned.
 Otherwise, @var{pattern} contains an engine specific expression that
 is used to limit the list to all keys matching the pattern.
 
 @var{mode} is usually 0; other values are described above.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{keydata} is not a valid empty data buffer, and passes through any
 errors that are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_export_start (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_export_start} initiates a
 @code{gpgme_op_export} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{keydata} is not a valid empty data buffer.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_export_ext (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}[]}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_export} extracts public keys and returns
 them in the data buffer @var{keydata}.  The output format of the key
 data returned is determined by the @acronym{ASCII} armor attribute set
 for the context @var{ctx}, or, if that is not set, by the encoding
 specified for @var{keydata}.
 
 If @var{pattern} or @var{*pattern} is @code{NULL}, all available keys
 are returned.  Otherwise, @var{pattern} is a @code{NULL} terminated
 array of strings that are used to limit the list to all keys matching
 at least one of the patterns verbatim.
 
 @var{mode} is usually 0; other values are described above.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{keydata} is not a valid empty data buffer, and passes through any
 errors that are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_export_ext_start (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{pattern}[]}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_export_ext_start} initiates a
 @code{gpgme_op_export_ext} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{keydata} is not a valid empty data buffer.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_export_keys (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t keys[]}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 @since{1.2.0}
 
 The function @code{gpgme_op_export_keys} extracts public keys and returns
 them in the data buffer @var{keydata}.  The output format of the key
 data returned is determined by the @acronym{ASCII} armor attribute set
 for the context @var{ctx}, or, if that is not set, by the encoding
 specified for @var{keydata}.
 
 The keys to export are taken form the @code{NULL} terminated array
 @var{keys}.  Only keys of the currently selected protocol of
 @var{ctx} which do have a fingerprint set are considered for export.
 Other keys specified by the @var{keys} are ignored.  In particular
 OpenPGP keys retrieved via an external key listing are not included.
 
 @var{mode} is usually 0; other values are described above.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{keydata} is not a valid empty data buffer, @code{GPG_ERR_NO_DATA}
 if no useful keys are in @var{keys} and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_export_keys_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{keys}[]}, @w{gpgme_export_mode_t @var{mode}}, @w{gpgme_data_t @var{keydata}})
 @since{1.2.0}
 
 The function @code{gpgme_op_export_keys_start} initiates a
 @code{gpgme_op_export_ext} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{keydata} is not a valid empty data buffer, @code{GPG_ERR_NO_DATA}
 if no useful keys are in @var{keys} and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 
 @node Importing Keys
 @subsection Importing Keys
 @cindex key, import
 @cindex key ring, import to
 
 Importing keys means the same as running @command{gpg} with the command
 @option{--import}.
 
 
 @deftypefun gpgme_error_t gpgme_op_import (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_import} adds the keys in the data buffer
 @var{keydata} to the key ring of the crypto engine used by @var{ctx}.
 The format of @var{keydata} can be @acronym{ASCII} armored, for example,
 but the details are specific to the crypto engine.
 
 After the operation completed successfully, the result can be
 retrieved with @code{gpgme_op_import_result}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 import was completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{keydata} if @var{ctx} or @var{keydata} is not a valid pointer,
 and @code{GPG_ERR_NO_DATA} if @var{keydata} is an empty data buffer.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_import_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{keydata}})
 The function @code{gpgme_op_import_start} initiates a
 @code{gpgme_op_import} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 import could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{keydata} is not a valid pointer, and
 @code{GPG_ERR_NO_DATA} if @var{keydata} is an empty data buffer.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_import_keys (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t *@var{keys}})
 @since{1.2.0}
 
 The function @code{gpgme_op_import_keys} adds the keys described by
 the @code{NULL} terminated array @var{keys} to the key ring of the
 crypto engine used by @var{ctx}.  It is used to actually import and
 make keys permanent which have been retrieved from an external source
 (i.e. using @code{GPGME_KEYLIST_MODE_EXTERN}) earlier.  The external
 keylisting must have been made with the same context configuration (in
 particular the same home directory).  @footnote{Thus it is a
 replacement for the usual workaround of exporting and then importing a
 key to make an X.509 key permanent.}  Note that for OpenPGP this may
 require another access to the keyserver over the network.
 
 Only keys of the currently selected protocol of @var{ctx} are
 considered for import.  Other keys specified by the @var{keys} are
 ignored.  As of now all considered keys must have been retrieved using
 the same method, i.e. the used key listing mode must be identical.
 
 After the operation completed successfully, the result can be
 retrieved with @code{gpgme_op_import_result}.
 
 To move keys from one home directory to another, export and import the
 keydata using @code{gpgme_op_export} and @code{gpgme_op_import}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 import was completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx} is not a valid pointer, @code{GPG_ERR_CONFLICT} if the key
 listing mode does not match, and @code{GPG_ERR_NO_DATA} if no keys are
 considered for export.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_import_keys_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t *@var{keys}})
 @since{1.2.0}
 
 The function @code{gpgme_op_import_keys_start} initiates a
 @code{gpgme_op_import_keys} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 import was completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{keydata} if @var{ctx} or @var{keydata} is not a valid pointer,
 @code{GPG_ERR_CONFLICT} if the key listing mode does not match, and
 @code{GPG_ERR_NO_DATA} if no keys are considered for export.
 @end deftypefun
 
 @deftp {Data type} {gpgme_import_status_t}
 This is a pointer to a structure used to store a part of the result of
 a @code{gpgme_op_import} operation.  For each considered key one
 status is added that contains information about the result of the
 import.  The structure contains the following members:
 
 @table @code
 @item gpgme_import_status_t next
 This is a pointer to the next status structure in the linked list, or
 @code{NULL} if this is the last element.
 
 @item char *fpr
 This is the fingerprint of the key that was considered.
 
 @item gpgme_error_t result
 If the import was not successful, this is the error value that caused
 the import to fail.  Otherwise the error code is
 @code{GPG_ERR_NO_ERROR}.
 
 @item unsigned int status
 This is a bit-wise OR of the following flags that give more
 information about what part of the key was imported.  If the key was
 already known, this might be 0.
 
 @table @code
 @item GPGME_IMPORT_NEW
 The key was new.
 
 @item GPGME_IMPORT_UID
 The key contained new user IDs.
 
 @item GPGME_IMPORT_SIG
 The key contained new signatures.
 
 @item GPGME_IMPORT_SUBKEY
 The key contained new sub keys.
 
 @item GPGME_IMPORT_SECRET
 The key contained a secret key.
 @end table
 @end table
 @end deftp
 
 @deftp {Data type} {gpgme_import_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_import} operation.  After a successful import
 operation, you can retrieve the pointer to the result with
 @code{gpgme_op_import_result}.  The structure contains the following
 members:
 
 @table @code
 @item int considered
 The total number of considered keys.
 
 @item int no_user_id
 The number of keys without user ID.
 
 @item int imported
 The total number of imported keys.
 
 @item int imported_rsa
 The number of imported RSA keys.
 
 @item int unchanged
 The number of unchanged keys.
 
 @item int new_user_ids
 The number of new user IDs.
 
 @item int new_sub_keys
 The number of new sub keys.
 
 @item int new_signatures
 The number of new signatures.
 
 @item int new_revocations
 The number of new revocations.
 
 @item int secret_read
 The total number of secret keys read.
 
 @item int secret_imported
 The number of imported secret keys.
 
 @item int secret_unchanged
 The number of unchanged secret keys.
 
 @item int not_imported
 The number of keys not imported.
 
 @item gpgme_import_status_t imports
 A list of gpgme_import_status_t objects which contain more information
 about the keys for which an import was attempted.
 
 @item int skipped_v3_keys
 For security reasons modern versions of GnuPG do not anymore support
 v3 keys (created with PGP 2.x) and ignores them on import.  This
 counter provides the number of such skipped v3 keys.
 
 @end table
 @end deftp
 
 @deftypefun gpgme_import_result_t gpgme_op_import_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_import_result} returns a
 @code{gpgme_import_result_t} pointer to a structure holding the result
 of a @code{gpgme_op_import} operation.  The pointer is only valid if
 the last operation on the context was a @code{gpgme_op_import} or
 @code{gpgme_op_import_start} operation, and if this operation finished
 successfully.  The returned pointer is only valid until the next
 operation is started on the context.
 @end deftypefun
 
 @node Deleting Keys
 @subsection Deleting Keys
 @cindex key, delete
 @cindex key ring, delete from
 
 @deftypefun gpgme_error_t gpgme_op_delete_ext (@w{gpgme_ctx_t @var{ctx}}, @w{const gpgme_key_t @var{key}}, @w{unsigned int @var{flags}})
 @since{1.9.1}
 
 The function @code{gpgme_op_delete_ext} deletes the key @var{key} from
 the key ring of the crypto engine used by @var{ctx}.
 
 @var{flags} can be set to the bit-wise OR of the following flags:
 
 @table @code
 @item GPGME_DELETE_ALLOW_SECRET
 @since{1.9.1}
 
 If not set, only public keys are deleted. If set, secret keys are
 deleted as well, if that is supported.
 
 @item GPGME_DELETE_FORCE
 @since{1.9.1}
 
 If set, the user is not asked to confirm the deletion.
 @end table
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the key
 was deleted successfully, @code{GPG_ERR_INV_VALUE} if @var{ctx} or
 @var{key} is not a valid pointer, @code{GPG_ERR_NO_PUBKEY} if
 @var{key} could not be found in the keyring,
 @code{GPG_ERR_AMBIGUOUS_NAME} if the key was not specified
 unambiguously, and @code{GPG_ERR_CONFLICT} if the secret key for
 @var{key} is available, but @var{allow_secret} is zero.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_delete_ext_start (@w{gpgme_ctx_t @var{ctx}}, @w{const gpgme_key_t @var{key}}, @w{unsigned int @var{flags}})
 @since{1.9.1}
 
 The function @code{gpgme_op_delete_ext_start} initiates a
 @code{gpgme_op_delete} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation was started successfully, and @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{key} is not a valid pointer.
 @end deftypefun
 
 The following functions allow only to use one particular flag.
 
 @deftypefun gpgme_error_t gpgme_op_delete (@w{gpgme_ctx_t @var{ctx}}, @w{const gpgme_key_t @var{key}}, @w{int @var{allow_secret}})
 Similar to @code{gpgme_op_delete_ext}, but only the flag
 @code{GPGME_DELETE_ALLOW_SECRET} can be provided.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_delete_start (@w{gpgme_ctx_t @var{ctx}}, @w{const gpgme_key_t @var{key}}, @w{int @var{allow_secret}})
 Similar to @code{gpgme_op_delete_ext_start}, but only the flag
 @code{GPGME_DELETE_ALLOW_SECRET} can be provided.
 @end deftypefun
 
 
 @node Changing Passphrases
 @subsection Changing Passphrases
 @cindex passphrase, change
 
 @deftypefun gpgme_error_t gpgme_op_passwd      @
              (@w{gpgme_ctx_t @var{ctx}},       @
               @w{const gpgme_key_t @var{key}}, @
               @w{unsigned int @var{flags}})
 
 @since{1.3.0}
 
 The function @code{gpgme_op_passwd} changes the passphrase of the
 private key associated with @var{key}.  The only allowed value for
 @var{flags} is @code{0}.  The backend engine will usually popup a window
 to ask for the old and the new passphrase.  Thus this function is not
 useful in a server application (where passphrases are not required
 anyway).
 
 Note that old @code{gpg} engines (before version 2.0.15) do not support
 this command and will silently ignore it.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_passwd_start      @
              (@w{gpgme_ctx_t @var{ctx}},       @
               @w{const gpgme_key_t @var{key}}, @
               @w{unsigned int @var{flags}})
 
 @since{1.3.0}
 
 The function @code{gpgme_op_passwd_start} initiates a
 @code{gpgme_op_passwd} operation.    It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns @code{0} if the operation was started successfully,
 and an error code if one of the arguments is not valid or the oepration
 could not be started.
 @end deftypefun
 
 
 @c
 @c  CHANGING TOFU DATA
 @c
 @node Changing TOFU Data
 @subsection Changing TOFU Data
 @cindex validity, TOFU
 
 The OpenPGP engine features a Trust-On-First-Use (TOFU) key validation
 model.  For resolving conflicts it is necessary to declare the policy
 for a key.  See the GnuPG manual for details on the TOFU
 implementation.
 
 @deftp {Data type} {enum gpgme_tofu_policy_t}
 @since{1.7.0}
 
 @tindex gpgme_tofu_policy_t
 The @code{gpgme_tofu_policy_t} type specifies the set of possible
 policy values that are supported by @acronym{GPGME}:
 
 @table @code
 @item GPGME_TOFU_POLICY_AUTO
 Set the policy to ``auto''.
 @item GPGME_TOFU_POLICY_GOOD
 Set the policy to ``good''.
 @item GPGME_TOFU_POLICY_BAD
 Set the policy to ``bad''.
 @item GPGME_TOFU_POLICY_ASK
 Set the policy to ``ask''.
 @item GPGME_TOFU_POLICY_UNKNOWN
 Set the policy to ``unknown''.
 @end table
 
 @end deftp
 
 To change the policy for a key the following functions can be used:
 
 @deftypefun gpgme_error_t gpgme_op_tofu_policy @
              (@w{gpgme_ctx_t @var{ctx}},       @
               @w{const gpgme_key_t @var{key}}, @
               @w{gpgme_tofu_policy_t @var{policy}})
 
 @since{1.7.0}
 
 The function @code{gpgme_op_tofu_policy} changes the TOFU policy of
 @var{key}.  The valid values for @var{policy} are listed above.  As of
 now this function does only work for OpenPGP and requires at least
 version 2.1.10 of GnuPG.
 
 The function returns zero on success, @code{GPG_ERR_NOT_SUPPORTED} if
 the engine does not support the command, or a bunch of other error
 codes.
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_tofu_policy_start @
              (@w{gpgme_ctx_t @var{ctx}},       @
               @w{const gpgme_key_t @var{key}}, @
               @w{gpgme_tofu_policy_t @var{policy}})
 
 @since{1.7.0}
 
 The function @code{gpgme_op_tofu_policy_start} initiates a
 @code{gpgme_op_tofu_policy} operation.    It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns @code{0} if the operation was started successfully,
 and an error code if one of the arguments is not valid or the oepration
 could not be started.
 
 @end deftypefun
 
 
 @node Advanced Key Editing
 @subsection Advanced Key Editing
 @cindex key, edit
 
 @deftp {Data type} {gpgme_error_t (*gpgme_interact_cb_t) @
    (@w{void *@var{handle}}, @
     @w{const char *@var{status}}, @
     @w{const char *@var{args}}, @
     @w{int @var{fd}})}
 
 @since{1.7.0}
 
 @tindex gpgme_interact_cb_t
 The @code{gpgme_interact_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it a key interact operation is on-going.  The
 status keyword @var{status} and the argument line @var{args} are
 passed through by @acronym{GPGME} from the crypto engine.  An empty
 string represents EOF.  The file descriptor @var{fd} is -1 for normal
 status messages.  If @var{status} indicates a command rather than a
 status message, the response to the command should be written to
 @var{fd}.  The @var{handle} is provided by the user at start of
 operation.
 
 The function should return @code{GPG_ERR_FALSE} if it did not handle
 the status code, @code{0} for success, or any other error value.
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_op_interact (@w{gpgme_ctx_t @var{ctx}}, @
    @w{gpgme_key_t @var{key}}, @
    @w{unsigned int @var{flags}}, @
    @w{gpgme_interact_cb_t @var{fnc}}, @
    @w{void *@var{handle}}, @
    @w{gpgme_data_t @var{out}})
 
 @since{1.7.0}
 
 The function @code{gpgme_op_interact} processes the key @var{KEY}
 interactively, using the interact callback function @var{FNC} with the
 handle @var{HANDLE}.  The callback is invoked for every status and
 command request from the crypto engine.  The output of the crypto
 engine is written to the data object @var{out}.
 
 Note that the protocol between the callback function and the crypto
 engine is specific to the crypto engine and no further support in
 implementing this protocol correctly is provided by @acronym{GPGME}.
 
 @var{flags} modifies the behaviour of the function; the only defined
 bit value is:
 
 @table @code
 @item GPGME_INTERACT_CARD
 @since{1.7.0}
 
 This is used for smartcard based keys and uses gpg’s
 @code{--card-edit} command.
 
 @end table
 
 The function returns @code{0} if the edit operation completes
 successfully, @code{GPG_ERR_INV_VALUE} if @var{ctx} or @var{key} is
 not a valid pointer, and any error returned by the crypto engine or
 the edit callback handler.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_interact_start (@w{gpgme_ctx_t @var{ctx}}, @
    @w{gpgme_key_t @var{key}}, @
    @w{unsigned int @var{flags}}, @
    @w{gpgme_interact_cb_t @var{fnc}}, @
    @w{void *@var{handle}}, @
    @w{gpgme_data_t @var{out}})
 
 @since{1.7.0}
 
 The function @code{gpgme_op_interact_start} initiates a
 @code{gpgme_op_interact} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns @code{0} if the operation was started
 successfully, and @code{GPG_ERR_INV_VALUE} if @var{ctx} or @var{key}
 is not a valid pointer.
 @end deftypefun
 
 
 @node Crypto Operations
 @section Crypto Operations
 @cindex cryptographic operation
 
 Sometimes, the result of a crypto operation returns a list of invalid
 keys encountered in processing the request.  The following structure
 is used to hold information about such a key.
 
 @deftp {Data type} {gpgme_invalid_key_t}
 This is a pointer to a structure used to store a part of the result of
 a crypto operation which takes user IDs as one input parameter.  The
 structure contains the following members:
 
 @table @code
 @item gpgme_invalid_key_t next
 This is a pointer to the next invalid key structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item char *fpr
 The fingerprint or key ID of the invalid key encountered.
 
 @item gpgme_error_t reason
 An error code describing the reason why the key was found invalid.
 @end table
 @end deftp
 
 
 @menu
 * Decrypt::                       Decrypting a ciphertext.
 * Verify::                        Verifying a signature.
 * Decrypt and Verify::            Decrypting a signed ciphertext.
 * Sign::                          Creating a signature.
 * Encrypt::                       Encrypting a plaintext.
 @end menu
 
 
 @node Decrypt
 @subsection Decrypt
 @cindex decryption
 @cindex cryptographic operation, decryption
 
 @deftypefun gpgme_error_t gpgme_op_decrypt (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{cipher}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_decrypt} decrypts the ciphertext in the
 data object @var{cipher} and stores it into the data object
 @var{plain}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 ciphertext could be decrypted successfully, @code{GPG_ERR_INV_VALUE}
 if @var{ctx}, @var{cipher} or @var{plain} is not a valid pointer,
 @code{GPG_ERR_NO_DATA} if @var{cipher} does not contain any data to
 decrypt, @code{GPG_ERR_DECRYPT_FAILED} if @var{cipher} is not a valid
 cipher text, @code{GPG_ERR_BAD_PASSPHRASE} if the passphrase for the
 secret key could not be retrieved, and passes through some errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_decrypt_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{cipher}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_decrypt_start} initiates a
 @code{gpgme_op_decrypt} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{cipher} or @var{plain} is not a valid pointer.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_decrypt_ext ( @
             @w{gpgme_ctx_t @var{ctx}}, @
             @w{gpgme_decrypt_flags_t @var{flags}}, @
             @w{gpgme_data_t @var{cipher}}, @
             @w{gpgme_data_t @var{plain}})
 
 @since{1.8.0}
 
 The function @code{gpgme_op_decrypt_ext} is the same as
 @code{gpgme_op_decrypt} but has an additional argument
 @var{flags}.  If @var{flags} is 0 both function behave identically.
 
 The value in @var{flags} is a bitwise-or combination of one or
 multiple of the following bit values:
 
 @table @code
 @item GPGME_DECRYPT_VERIFY
 @since{1.8.0}
 
 The @code{GPGME_DECRYPT_VERIFY} symbol specifies that this function
 shall exactly act as @code{gpgme_op_decrypt_verify}.
 
 @item GPGME_DECRYPT_UNWRAP
 @since{1.8.0}
 
 The @code{GPGME_DECRYPT_UNWRAP} symbol specifies that the output shall
 be an OpenPGP message with only the encryption layer removed.  This
 requires GnuPG 2.1.12 and works only for OpenPGP.  This is the
 counterpart to @code{GPGME_ENCRYPT_WRAP}.
 
 @end table
 
 The function returns the error codes as described for
 @code{gpgme_op_decrypt}.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_decrypt_ext_start ( @
             @w{gpgme_ctx_t @var{ctx}}, @
             @w{gpgme_decrypt_flags_t @var{flags}}, @
             @w{gpgme_data_t @var{cipher}}, @
             @w{gpgme_data_t @var{plain}})
 
 @since{1.8.0}
 
 The function @code{gpgme_op_decrypt_ext_start} initiates a
 @code{gpgme_op_decrypt_ext} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{cipher} or @var{plain} is not a valid pointer.
 @end deftypefun
 
 
 @deftp {Data type} {gpgme_recipient_t}
 @since{1.1.0}
 
 This is a pointer to a structure used to store information about the
 recipient of an encrypted text which is decrypted in a
 @code{gpgme_op_decrypt} operation.  This information (except for the
 status field) is even available before the operation finished
 successfully, for example in a passphrase callback.  The structure
 contains the following members:
 
 @table @code
 @item gpgme_recipient_t next
 This is a pointer to the next recipient structure in the linked list,
 or @code{NULL} if this is the last element.
 
 @item gpgme_pubkey_algo_t
 The public key algorithm used in the encryption.
 
 @item char *keyid
 This is the key ID of the key (in hexadecimal digits) used as
 recipient.
 
 @item gpgme_error_t status
 This is an error number with the error code GPG_ERR_NO_SECKEY if the
 secret key for this recipient is not available, and 0 otherwise.
 @end table
 @end deftp
 
 @deftp {Data type} {gpgme_decrypt_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_decrypt} operation.  After successfully decrypting
 data, you can retrieve the pointer to the result with
 @code{gpgme_op_decrypt_result}.  As with all result structures, it
 this structure shall be considered read-only and an application must
 not allocate such a strucure on its own.  The structure contains the
 following members:
 
 @table @code
 @item char *unsupported_algorithm
 If an unsupported algorithm was encountered, this string describes the
 algorithm that is not supported.
 
 @item unsigned int wrong_key_usage : 1
 @since{0.9.0}
 This is true if the key was not used according to its policy.
 
 @item unsigned int legacy_cipher_nomdc : 1
 @since{1.11.2}
 The message was made by a legacy algorithm without any integrity
 protection.  This might be an old but legitimate message.
 
 @item unsigned int is_mime : 1;
 @since{1.11.0}
 The message claims that the content is a MIME object.
 
 @item unsigned int is_de_vs : 1;
 @since{1.10.0}
 The message was encrypted in a VS-NfD compliant way.  This is a
 specification in Germany for a restricted communication level.
 
 @item gpgme_recipient_t recipients
 @since{1.1.0}
 
 This is a linked list of recipients to which this message was encrypted.
 
 @item char *file_name
 This is the filename of the original plaintext message file if it is
 known, otherwise this is a null pointer.
 
 @item char *session_key
 @since{1.8.0}
 
 A textual representation (nul-terminated string) of the session key
 used in symmetric encryption of the message, if the context has been
 set to export session keys (see @code{gpgme_set_ctx_flag,
 "export-session-key"}), and a session key was available for the most
 recent decryption operation.  Otherwise, this is a null pointer.
 
 You must not try to access this member of the struct unless
 @code{gpgme_set_ctx_flag (ctx, "export-session-key")} returns success
 or @code{gpgme_get_ctx_flag (ctx, "export-session-key")} returns true
 (non-empty string).
 
 @item char *symkey_algo
 @since{1.11.0}
 
 A string with the symmetric encryption algorithm and mode using the
 format "<algo>.<mode>".  Note that the deprecated non-MDC encryption mode of
 OpenPGP is given as "PGPCFB".
 
 @end table
 @end deftp
 
 @deftypefun gpgme_decrypt_result_t gpgme_op_decrypt_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_decrypt_result} returns a
 @code{gpgme_decrypt_result_t} pointer to a structure holding the
 result of a @code{gpgme_op_decrypt} operation.  The pointer is only
 valid if the last operation on the context was a
 @code{gpgme_op_decrypt} or @code{gpgme_op_decrypt_start} operation.
 If the operation failed this might be a @code{NULL} pointer.  The
 returned pointer is only valid until the next operation is started on
 the context.
 @end deftypefun
 
 
 @node Verify
 @subsection Verify
 @cindex verification
 @cindex signature, verification
 @cindex cryptographic operation, verification
 @cindex cryptographic operation, signature check
 @cindex signature notation data
 @cindex notation data
 
 @deftypefun gpgme_error_t gpgme_op_verify (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{sig}}, @w{gpgme_data_t @var{signed_text}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_verify} verifies that the signature in the
 data object @var{sig} is a valid signature.  If @var{sig} is a
 detached signature, then the signed text should be provided in
 @var{signed_text} and @var{plain} should be a null pointer.
 Otherwise, if @var{sig} is a normal (or cleartext) signature,
 @var{signed_text} should be a null pointer and @var{plain} should be a
 writable data object that will contain the plaintext after successful
 verification.
 
 The results of the individual signature verifications can be retrieved
 with @code{gpgme_op_verify_result}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be completed successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{sig} or @var{plain} is not a valid pointer,
 @code{GPG_ERR_NO_DATA} if @var{sig} does not contain any data to
 verify, and passes through any errors that are reported by the crypto
 engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_verify_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{sig}}, @w{gpgme_data_t @var{signed_text}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_verify_start} initiates a
 @code{gpgme_op_verify} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{sig} or @var{plain} is not a valid pointer, and
 @code{GPG_ERR_NO_DATA} if @var{sig} or @var{plain} does not contain
 any data to verify.
 @end deftypefun
 
 @deftp {Data type} {gpgme_sig_notation_t}
 This is a pointer to a structure used to store a part of the result of
 a @code{gpgme_op_verify} operation.  The structure contains the
 following members:
 
 @table @code
 @item gpgme_sig_notation_t next
 This is a pointer to the next new signature notation structure in the
 linked list, or @code{NULL} if this is the last element.
 
 @item char *name
 The name of the notation field.  If this is @code{NULL}, then the
 member @code{value} will contain a policy URL.
 
 @item int name_len
 The length of the @code{name} field.  For strings the length is
 counted without the trailing binary zero.
 
 @item char *value
 The value of the notation field.  If @code{name} is @code{NULL}, then
 this is a policy URL.
 
 @item int value_len
 The length of the @code{value} field.  For strings the length is
 counted without the trailing binary zero.
 
 @item gpgme_sig_notation_flags_t flags
 The accumulated flags field.  This field contains the flags associated
 with the notation data in an accumulated form which can be used as an
 argument to the function @code{gpgme_sig_notation_add}.  The value
 @code{flags} is a bitwise-or combination of one or multiple of the
 following bit values:
 
 @table @code
 @item GPGME_SIG_NOTATION_HUMAN_READABLE
 @since{1.1.0}
 
 The @code{GPGME_SIG_NOTATION_HUMAN_READABLE} symbol specifies that the
 notation data is in human readable form
 
 @item GPGME_SIG_NOTATION_CRITICAL
 @since{1.1.0}
 
 The @code{GPGME_SIG_NOTATION_CRITICAL} symbol specifies that the
 notation data is critical.
 
 @end table
 
 @item unsigned int human_readable : 1
 This is true if the @code{GPGME_SIG_NOTATION_HUMAN_READABLE} flag is
 set and false otherwise.  This flag is only valid for notation data,
 not for policy URLs.
 
 @item unsigned int critical : 1
 This is true if the @code{GPGME_SIG_NOTATION_CRITICAL} flag is set and
 false otherwise.  This flag is valid for notation data and policy URLs.
 
 @end table
 @end deftp
 
 @deftp {Data type} {gpgme_signature_t}
 This is a pointer to a structure used to store a part of the result of
 a @code{gpgme_op_verify} operation.  The structure contains the
 following members:
 
 @table @code
 @item gpgme_signature_t next
 This is a pointer to the next new signature structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item gpgme_sigsum_t summary
 This is a bit vector giving a summary of the signature status.  It
 provides an easy interface to a defined semantic of the signature
 status.  Checking just one bit is sufficient to see whether a
 signature is valid without any restrictions. This means that
 you can check for GPGME_SIGSUM_VALID like this:
 
 @example
 if ((sig.summary & GPGME_SIGSUM_VALID))
 @{
    ..do stuff if valid..
 @}
 else
 @{
    ..do stuff if not fully valid..
 @}
 @end example
 
 The defined bits are:
   @table @code
   @item GPGME_SIGSUM_VALID
   The signature is fully valid.
 
   @item GPGME_SIGSUM_GREEN
   The signature is good but one might want to display some extra
   information.  Check the other bits.
 
   @item GPGME_SIGSUM_RED
   The signature is bad. It might be useful to check other bits and
   display more information, i.e. a revoked certificate might not render a
   signature invalid when the message was received prior to the cause for
   the revocation.
 
   @item GPGME_SIGSUM_KEY_REVOKED
   The key or at least one certificate has been revoked.
 
   @item GPGME_SIGSUM_KEY_EXPIRED
   The key or one of the certificates has expired. It is probably a good
   idea to display the date of the expiration.
 
   @item GPGME_SIGSUM_SIG_EXPIRED
   The signature has expired.
 
   @item GPGME_SIGSUM_KEY_MISSING
   Can't verify due to a missing key or certificate.
 
   @item GPGME_SIGSUM_CRL_MISSING
   The CRL (or an equivalent mechanism) is not available.
 
   @item GPGME_SIGSUM_CRL_TOO_OLD
   Available CRL is too old.
 
   @item GPGME_SIGSUM_BAD_POLICY
   A policy requirement was not met.
 
   @item GPGME_SIGSUM_SYS_ERROR
   A system error occurred.
 
   @item GPGME_SIGSUM_TOFU_CONFLICT
   A TOFU conflict was detected.
   @end table
 
 @item char *fpr
 This is the fingerprint or key ID of the signature.
 
 @item gpgme_error_t status
 This is the status of the signature.  In particular, the following
 status codes are of interest:
 
   @table @code
   @item GPG_ERR_NO_ERROR
   This status indicates that the signature could be verified or that
   there is no signature.  For the combined result this status
   means that all signatures could be verified.
 
   Note: This does not mean that a valid signature could be found.  Check
   the @code{summary} field for that.
 
   For example a @code{gpgme_op_decrypt_verify} returns a verification
   result with GPG_ERR_NO_ERROR for encrypted but unsigned data.
 
   @item GPG_ERR_SIG_EXPIRED
   This status indicates that the signature is valid but expired.  For
   the combined result this status means that all signatures are valid
   and expired.
 
   @item GPG_ERR_KEY_EXPIRED
   This status indicates that the signature is valid but the key used to
   verify the signature has expired.  For the combined result this status
   means that all signatures are valid and all keys are expired.
 
   @item GPG_ERR_CERT_REVOKED
   This status indicates that the signature is valid but the key used
   to verify the signature has been revoked.  For the combined result
   this status means that all signatures are valid and all keys are
   revoked.
 
   @item GPG_ERR_BAD_SIGNATURE
   This status indicates that the signature is invalid.  For the combined
   result this status means that all signatures are invalid.
 
   @item GPG_ERR_NO_PUBKEY
   This status indicates that the signature could not be verified due to
   a missing key.  For the combined result this status means that all
   signatures could not be checked due to missing keys.
 
   @item GPG_ERR_GENERAL
   This status indicates that there was some other error which prevented
   the signature verification.
   @end table
 
 @item gpgme_sig_notation_t notations
 This is a linked list with the notation data and policy URLs.
 
 @item unsigned long timestamp
 The creation timestamp of this signature.
 
 @item unsigned long exp_timestamp
 The expiration timestamp of this signature, or 0 if the signature does
 not expire.
 
 @item unsigned int wrong_key_usage : 1
 This is true if the key was not used according to its policy.
 
 @item unsigned int pka_trust : 2
 This is set to the trust information gained by means of the PKA system.
 Values are:
   @table @code
   @item 0
         No PKA information available or verification not possible.
   @item 1
         PKA verification failed.
   @item 2
         PKA verification succeeded.
   @item 3
         Reserved for future use.
   @end table
 Depending on the configuration of the engine, this metric may also be
 reflected by the validity of the signature.
 
 @item unsigned int chain_model : 1
 @since{1.1.6}
 
 This is true if the validity of the signature has been checked using the
 chain model.  In the chain model the time the signature has been created
 must be within the validity period of the certificate and the time the
 certificate itself has been created must be within the validity period
 of the issuing certificate.  In contrast the default validation model
 checks the validity of signature as well at the entire certificate chain
 at the current time.
 
 
 @item gpgme_validity_t validity
 The validity of the signature.
 
 @item gpgme_error_t validity_reason
 If a signature is not valid, this provides a reason why.
 
 @item gpgme_pubkey_algo_t
 The public key algorithm used to create this signature.
 
 @item gpgme_hash_algo_t
 The hash algorithm used to create this signature.
 
 @item char *pka_address
 The mailbox from the PKA information or @code{NULL}.
 
 @item gpgme_key_t key
 @since{1.7.0}
 
 An object describing the key used to create the signature.  This key
 object may be incomplete in that it only conveys information
 availabale directly with a signature.  It may also be @code{NULL} if
 such information is not readily available.
 
 @end table
 @end deftp
 
 @deftp {Data type} {gpgme_verify_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_verify} operation.  After verifying a signature, you
 can retrieve the pointer to the result with
 @code{gpgme_op_verify_result}.  If the operation failed this might be
 a @code{NULL} pointer.  The structure contains the following member:
 
 @table @code
 @item gpgme_signature_t signatures
 A linked list with information about all signatures for which a
 verification was attempted.
 
 @item char *file_name
 This is the filename of the original plaintext message file if it is
 known, otherwise this is a null pointer.  Warning: The filename is
 not covered by the signature.
 
 @item unsigned int is_mime : 1;
 @since{1.11.0}
 
 The message claims that the content is a MIME object.  Warning: This
 flag is not covered by the signature.
 
 @end table
 @end deftp
 
 @deftypefun gpgme_verify_result_t gpgme_op_verify_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_verify_result} returns a
 @code{gpgme_verify_result_t} pointer to a structure holding the result
 of a @code{gpgme_op_verify} operation.  The pointer is only valid if
 the last operation on the context was a @code{gpgme_op_verify},
 @code{gpgme_op_verify_start}, @code{gpgme_op_decrypt_verify} or
 @code{gpgme_op_decrypt_verify_start} operation, and if this operation
 finished successfully (for @code{gpgme_op_decrypt_verify} and
 @code{gpgme_op_decrypt_verify_start}, the error code
 @code{GPG_ERR_NO_DATA} counts as successful in this context).  The
 returned pointer is only valid until the next operation is started on
 the context.
 @end deftypefun
 
 
 @node Decrypt and Verify
 @subsection Decrypt and Verify
 @cindex decryption and verification
 @cindex verification and decryption
 @cindex signature check
 @cindex cryptographic operation, decryption and verification
 
 @deftypefun gpgme_error_t gpgme_op_decrypt_verify (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{cipher}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_decrypt_verify} decrypts the ciphertext in
 the data object @var{cipher} and stores it into the data object
 @var{plain}.  If @var{cipher} contains signatures, they will be
 verified.
 
 After the operation completed, @code{gpgme_op_decrypt_result} and
 @code{gpgme_op_verify_result} can be used to retrieve more information
 about the signatures.
 
 If the error code @code{GPG_ERR_NO_DATA} is returned, @var{cipher}
 does not contain any data to decrypt.  However, it might still be
 signed.  The information about detected signatures is available with
 @code{gpgme_op_verify_result} in this case.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 ciphertext could be decrypted successfully, @code{GPG_ERR_INV_VALUE}
 if @var{ctx}, @var{cipher} or @var{plain} is not a valid pointer,
 @code{GPG_ERR_NO_DATA} if @var{cipher} does not contain any data to
 decrypt, @code{GPG_ERR_DECRYPT_FAILED} if @var{cipher} is not a valid
 cipher text, @code{GPG_ERR_BAD_PASSPHRASE} if the passphrase for the
 secret key could not be retrieved, and passes through any errors that
 are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_decrypt_verify_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{cipher}}, @w{gpgme_data_t @var{plain}})
 The function @code{gpgme_op_decrypt_verify_start} initiates a
 @code{gpgme_op_decrypt_verify} operation.  It can be completed by
 calling @code{gpgme_wait} on the context.  @xref{Waiting For
 Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{cipher}, @var{plain} or @var{r_stat} is not a valid
 pointer, and @code{GPG_ERR_NO_DATA} if @var{cipher} does not contain
 any data to decrypt.
 @end deftypefun
 
 When processing mails it is sometimes useful to extract the actual
 mail address (the ``addr-spec'') from a string.  GPGME provides this
 helper function which uses the same semantics as the internal
 functions in GPGME and GnuPG:
 
 @deftypefun @w{char *} gpgme_addrspec_from_uid (@w{const char *@var{uid}})
 
 @since{1.7.1}
 
 Return the mail address (called ``addr-spec'' in RFC-5322) from the
 string @var{uid} which is assumed to be a user id (called ``address''
 in RFC-5322).  All plain ASCII characters (i.e. those with bit 7
 cleared) in the result are converted to lowercase.  Caller must free
 the result using @code{gpgme_free}.  Returns @code{NULL} if no valid
 address was found (in which case @code{ERRNO} is set to @code{EINVAL})
 or for other errors.
 
 @end deftypefun
 
 
 @node Sign
 @subsection Sign
 @cindex signature, creation
 @cindex sign
 @cindex cryptographic operation, signing
 
 A signature can contain signatures by one or more keys.  The set of
 keys used to create a signatures is contained in a context, and is
 applied to all following signing operations in this context (until the
 set is changed).
 
 @menu
 * Selecting Signers::             How to choose the keys to sign with.
 * Creating a Signature::          How to create a signature.
 * Signature Notation Data::       How to add notation data to a signature.
 @end menu
 
 
 @node Selecting Signers
 @subsubsection Selecting Signers
 @cindex signature, selecting signers
 @cindex signers, selecting
 
 The key or the keys used to create a signature are stored in the
 context.  The following functions can be used to manipulate this list.
 If no signer has been set into the context a default key is used for
 signing.
 
 @deftypefun void gpgme_signers_clear (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_signers_clear} releases a reference for each
 key on the signers list and removes the list of signers from the
 context @var{ctx}.
 
 Every context starts with an empty list.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_signers_add (@w{gpgme_ctx_t @var{ctx}}, @w{const gpgme_key_t @var{key}})
 The function @code{gpgme_signers_add} adds the key @var{key} to the
 list of signers in the context @var{ctx}.
 
 Calling this function acquires an additional reference for the key.
 @end deftypefun
 
 @deftypefun @w{unsigned int} gpgme_signers_count (@w{const gpgme_ctx_t @var{ctx}})
 @since{1.4.3}
 
 The function @code{gpgme_signers_count} returns the number of signer keys in
 the context @var{ctx}.
 @end deftypefun
 
 @deftypefun gpgme_key_t gpgme_signers_enum (@w{const gpgme_ctx_t @var{ctx}}, @w{int @var{seq}})
 The function @code{gpgme_signers_enum} returns the @var{seq}th key in
 the list of signers in the context @var{ctx}.  An additional reference
 is acquired for the user.
 
 If @var{seq} is out of range, @code{NULL} is returned.
 @end deftypefun
 
 
 @node Creating a Signature
 @subsubsection Creating a Signature
 
 @deftp {Data type} {enum gpgme_sig_mode_t}
 @tindex gpgme_sig_mode_t
 The @code{gpgme_sig_mode_t} type is used to specify the desired type of a
 signature.  The following modes are available:
 
 @table @code
 @item GPGME_SIG_MODE_NORMAL
 A normal signature is made, the output includes the plaintext and the
 signature.
 
 @item GPGME_SIG_MODE_DETACH
 A detached signature is made.
 
 @item GPGME_SIG_MODE_CLEAR
 A clear text signature is made.  The @acronym{ASCII} armor and text
 mode settings of the context are ignored.
 @end table
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_op_sign (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{sig}}, @w{gpgme_sig_mode_t @var{mode}})
 The function @code{gpgme_op_sign} creates a signature for the text in
 the data object @var{plain} and returns it in the data object
 @var{sig}.  The type of the signature created is determined by the
 @acronym{ASCII} armor (or, if that is not set, by the encoding
 specified for @var{sig}), the text mode attributes set for the context
 @var{ctx} and the requested signature mode @var{mode}.
 
 After the operation completed successfully, the result can be
 retrieved with @code{gpgme_op_sign_result}.
 
 If an S/MIME signed message is created using the CMS crypto engine,
 the number of certificates to include in the message can be specified
 with @code{gpgme_set_include_certs}.  @xref{Included Certificates}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 signature could be created successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{plain} or @var{sig} is not a valid pointer,
 @code{GPG_ERR_NO_DATA} if the signature could not be created,
 @code{GPG_ERR_BAD_PASSPHRASE} if the passphrase for the secret key
 could not be retrieved, @code{GPG_ERR_UNUSABLE_SECKEY} if there are
 invalid signers, and passes through any errors that are reported by the
 crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_sign_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{sig}}, @w{gpgme_sig_mode_t @var{mode}})
 The function @code{gpgme_op_sign_start} initiates a
 @code{gpgme_op_sign} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the operation could be
 started successfully, and @code{GPG_ERR_INV_VALUE} if @var{ctx},
 @var{plain} or @var{sig} is not a valid pointer.
 @end deftypefun
 
 @deftp {Data type} {gpgme_new_signature_t}
 This is a pointer to a structure used to store a part of the result of
 a @code{gpgme_op_sign} operation.  The structure contains the
 following members:
 
 @table @code
 @item gpgme_new_signature_t next
 This is a pointer to the next new signature structure in the linked
 list, or @code{NULL} if this is the last element.
 
 @item gpgme_sig_mode_t type
 The type of this signature.
 
 @item gpgme_pubkey_algo_t pubkey_algo
 The public key algorithm used to create this signature.
 
 @item gpgme_hash_algo_t hash_algo
 The hash algorithm used to create this signature.
 
 @item unsigned int sig_class
 The signature class of this signature.
 
 @item long int timestamp
 The creation timestamp of this signature.
 
 @item char *fpr
 The fingerprint of the key which was used to create this signature.
 @end table
 @end deftp
 
 @deftp {Data type} {gpgme_sign_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_sign} operation.  After successfully generating a
 signature, you can retrieve the pointer to the result with
 @code{gpgme_op_sign_result}.  The structure contains the following
 members:
 
 @table @code
 @item gpgme_invalid_key_t invalid_signers
 A linked list with information about all invalid keys for which a
 signature could not be created.
 
 @item gpgme_new_signature_t signatures
 A linked list with information about all signatures created.
 @end table
 @end deftp
 
 @deftypefun gpgme_sign_result_t gpgme_op_sign_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_sign_result} returns a
 @code{gpgme_sign_result_t} pointer to a structure holding the result
 of a @code{gpgme_op_sign} operation.  The pointer is only valid if the
 last operation on the context was a @code{gpgme_op_sign},
 @code{gpgme_op_sign_start}, @code{gpgme_op_encrypt_sign} or
 @code{gpgme_op_encrypt_sign_start} operation.  If that operation
 failed, the function might return a @code{NULL} pointer. The returned
 pointer is only valid until the next operation is started on the
 context.
 @end deftypefun
 
 
 @node Signature Notation Data
 @subsubsection Signature Notation Data
 @cindex notation data
 @cindex signature notation data
 @cindex policy URL
 
 Using the following functions, you can attach arbitrary notation data
 to a signature.  This information is then available to the user when
 the signature is verified.
 
 @deftypefun void gpgme_sig_notation_clear (@w{gpgme_ctx_t @var{ctx}})
 @since{1.1.0}
 
 The function @code{gpgme_sig_notation_clear} removes the notation data
 from the context @var{ctx}.  Subsequent signing operations from this
 context will not include any notation data.
 
 Every context starts with an empty notation data list.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_sig_notation_add (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{name}}, @w{const char *@var{value}}, @w{gpgme_sig_notation_flags_t @var{flags}})
 @since{1.1.0}
 
 The function @code{gpgme_sig_notation_add} adds the notation data with
 the name @var{name} and the value @var{value} to the context
 @var{ctx}.
 
 Subsequent signing operations will include this notation data, as well
 as any other notation data that was added since the creation of the
 context or the last @code{gpgme_sig_notation_clear} operation.
 
 The arguments @var{name} and @var{value} must be @code{NUL}-terminated
 strings in human-readable form.  The flag
 @code{GPGME_SIG_NOTATION_HUMAN_READABLE} is implied
 (non-human-readable notation data is currently not supported).  The
 strings must be in UTF-8 encoding.
 
 If @var{name} is @code{NULL}, then @var{value} should be a policy URL.
 
 The function @code{gpgme_sig_notation_add} returns the error code
 @code{GPG_ERR_NO_ERROR} if the notation data could be added
 successfully, @code{GPG_ERR_INV_VALUE} if @var{ctx} is not a valid
 pointer, or if @var{name}, @var{value} and @var{flags} are an invalid
 combination.  The function also passes through any errors that are
 reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_sig_notation_t gpgme_sig_notation_get (@w{const gpgme_ctx_t @var{ctx}})
 @since{1.1.0}
 
 The function @code{gpgme_sig_notation_get} returns the linked list of
 notation data structures that are contained in the context @var{ctx}.
 
 If @var{ctx} is not a valid pointer, or there is no notation data
 added for this context, @code{NULL} is returned.
 @end deftypefun
 
 
 @node Encrypt
 @subsection Encrypt
 @cindex encryption
 @cindex cryptographic operation, encryption
 
 One plaintext can be encrypted for several recipients at the same
 time.  The list of recipients is created independently of any context,
 and then passed to the encryption operation.
 
 @menu
 * Encrypting a Plaintext::        How to encrypt a plaintext.
 @end menu
 
 
 @node Encrypting a Plaintext
 @subsubsection Encrypting a Plaintext
 
 @deftypefun gpgme_error_t gpgme_op_encrypt (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{recp}[]}, @w{gpgme_encrypt_flags_t @var{flags}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 The function @code{gpgme_op_encrypt} encrypts the plaintext in the
 data object @var{plain} for the recipients @var{recp} and stores the
 ciphertext in the data object @var{cipher}.  The type of the
 ciphertext created is determined by the @acronym{ASCII} armor (or, if
 that is not set, by the encoding specified for @var{cipher}) and the
 text mode attributes set for the context @var{ctx}.
 
 @var{recp} must be a @code{NULL}-terminated array of keys.  The user
 must keep references for all keys during the whole duration of the
 call (but see @code{gpgme_op_encrypt_start} for the requirements with
 the asynchronous variant).
 
 The value in @var{flags} is a bitwise-or combination of one or
 multiple of the following bit values:
 
 @table @code
 @item GPGME_ENCRYPT_ALWAYS_TRUST
 The @code{GPGME_ENCRYPT_ALWAYS_TRUST} symbol specifies that all the
 recipients in @var{recp} should be trusted, even if the keys do not
 have a high enough validity in the keyring.  This flag should be used
 with care; in general it is not a good idea to use any untrusted keys.
 
 @item GPGME_ENCRYPT_NO_ENCRYPT_TO
 @since{1.2.0}
 
 The @code{GPGME_ENCRYPT_NO_ENCRYPT_TO} symbol specifies that no
 default or hidden default recipients as configured in the crypto
 backend should be included.  This can be useful for managing different
 user profiles.
 
 @item GPGME_ENCRYPT_NO_COMPRESS
 @since{1.5.0}
 
 The @code{GPGME_ENCRYPT_NO_COMPRESS} symbol specifies that the
 plaintext shall not be compressed before it is encrypted.  This is
 in some cases useful if the length of the encrypted message
 may reveal information about the plaintext.
 
 @item GPGME_ENCRYPT_PREPARE
 @itemx GPGME_ENCRYPT_EXPECT_SIGN
 The @code{GPGME_ENCRYPT_PREPARE} symbol is used with the UI Server
 protocol to prepare an encryption (i.e. sending the
 @code{PREP_ENCRYPT} command).  With the
 @code{GPGME_ENCRYPT_EXPECT_SIGN} symbol the UI Server is advised to
 also expect a sign command.
 
 @item GPGME_ENCRYPT_SYMMETRIC
 @since{1.7.0}
 
 The @code{GPGME_ENCRYPT_SYMMETRIC} symbol specifies that the
 output should be additionally encrypted symmetrically even
 if recipients are provided. This feature is only supported
 for the OpenPGP crypto engine.
 
 @item GPGME_ENCRYPT_THROW_KEYIDS
 @since{1.8.0}
 
 The @code{GPGME_ENCRYPT_THROW_KEYIDS} symbols requests that the
 identifiers for the decrption keys are not included in the ciphertext.
 On the receiving side, the use of this flag may slow down the
 decryption process because all available secret keys must be tried.
 This flag is only honored for OpenPGP encryption.
 
 @item GPGME_ENCRYPT_WRAP
 @since{1.8.0}
 
 The @code{GPGME_ENCRYPT_WRAP} symbol specifies that the input is an
 OpenPGP message and not a plain data.  This is the counterpart to
 @code{GPGME_DECRYPT_UNWRAP}.
 
 @item GPGME_ENCRYPT_WANT_ADDRESS
 @since{1.11.0}
 
 The @code{GPGME_ENCRYPT_WANT_ADDRESS} symbol requests that all
 supplied keys or key specifications include a syntactically valid mail
 address.  If this is not the case the operation is not even tried and
 the error code @code{GPG_ERR_INV_USER_ID} is returned.  Only the
 address part of the key specification is conveyed to the backend.  As
 of now the key must be specified using the @var{recpstring} argument
 of the extended encrypt functions.  This feature is currently only
 supported for the OpenPGP crypto engine.
 
 @end table
 
 If @code{GPG_ERR_UNUSABLE_PUBKEY} is returned, some recipients in
 @var{recp} are invalid, but not all.  In this case the plaintext might
 be encrypted for all valid recipients and returned in @var{cipher} (if
 this happens depends on the crypto engine).  More information about
 the invalid recipients is available with
 @code{gpgme_op_encrypt_result}.
 
 If @var{recp} is @code{NULL}, symmetric rather than public key
 encryption is performed.  Symmetrically encrypted cipher text can be
 deciphered with @code{gpgme_op_decrypt}.  Note that in this case the
 crypto backend needs to retrieve a passphrase from the user.
 Symmetric encryption is currently only supported for the OpenPGP
 crypto backend.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 ciphertext could be created successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{recp}, @var{plain} or @var{cipher} is not a valid
 pointer, @code{GPG_ERR_UNUSABLE_PUBKEY} if @var{recp} contains some
 invalid recipients, @code{GPG_ERR_BAD_PASSPHRASE} if the passphrase
 for the symmetric key could not be retrieved, and passes through any
 errors that are reported by the crypto engine support routines.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{recp}[]}, @w{gpgme_encrypt_flags_t @var{flags}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 The function @code{gpgme_op_encrypt_start} initiates a
 @code{gpgme_op_encrypt} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 References to the keys only need to be held for the duration of this
 call.  The user can release its references to the keys after this
 function returns, even if the operation is not yet finished.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx}, @var{rset}, @var{plain} or @var{cipher} is not a valid
 pointer, and @code{GPG_ERR_UNUSABLE_PUBKEY} if @var{rset} does not
 contain any valid recipients.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_ext @
             (@w{gpgme_ctx_t @var{ctx}}, @
              @w{gpgme_key_t @var{recp}[]}, @
              @w{const char *@var{recpstring}}, @
              @w{gpgme_encrypt_flags_t @var{flags}}, @
              @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 
 @since{1.11.0}
 
 This is an extended version of @code{gpgme_op_encrypt} with
 @var{recpstring} as additional parameter.  If @var{recp} is NULL and
 @var{recpstring} is not NULL, the latter is expected to be a linefeed
 delimited string with the set of key specifications.  In contrast to
 @var{recp} the keys are given directly as strings and there is no need
 to first create key objects.  Leading and trailing white space is
 remove from each line in @var{recpstring}.  The keys are then passed
 verbatim to the backend engine.
 
 For the OpenPGP backend several special keywords are supported to
 modify the operation.  These keywords are given instead of a key
 specification.  The currently supported keywords are:
 
 @table @code
 @item --hidden
 @itemx --no-hidden
 These keywords toggle between normal and hidden recipients for all
 following key specifications.  When a hidden recipient is requested
 the gpg option @option{-R} (or @option{-F} in file mode) is used
 instead of @option{-r} (@option{-f} in file mode).
 
 @item --file
 @itemx --no-file
 These keywords toggle between regular and file mode for all following
 key specification.  In file mode the option @option{-f} or @option{-F}
 is passed to gpg.  At least GnuPG version 2.1.14 is required to handle
 these options.  The @code{GPGME_ENCRYPT_WANT_ADDRESS} flag is ignored
 in file mode.
 
 @item --
 This keyword disables all keyword detection up to the end of the
 string.  All keywords are treated as verbatim arguments.
 
 @end table
 
 To create a @var{recpstring} it is often useful to employ a strconcat
 style function.  For example this function creates a string to encrypt
 to two keys:
 
 @example
 char *
 xbuild_recpstring (const char *key1, const char *key2)
 @{
   char *result = gpgrt_strconcat ("--\n", key1, "\n", key2, NULL);
   if (!result)
     @{ perror ("strconcat failed"); exit (2); @}
   return result;
 @}
 @end example
 
 Note the use of the double dash here; unless you want to specify a
 keyword, it is a good idea to avoid any possible trouble with key
 specifications starting with a double dash.  The used strconcat
 function is available in Libgpg-error 1.28 and later; Libgpg-error
 (aka Gpgrt) is a dependency of GPGME.  The number of arguments to
 @code{gpgrt_strconcat} is limited to 47 but that should always be
 sufficient.  In case a larger and non-fixed number of keys are to be
 supplied the following code can be used:
 
 @example
 char *
 xbuild_long_recpstring (void)
 @{
   gpgrt_stream_t memfp;
   const char *s;
   void *result;
 
   memfp = gpgrt_fopenmem (0, "w+b");
   if (!memfp)
     @{ perror ("fopenmem failed"); exit (2); @}
   gpgrt_fputs ("--", memfp);
   while ((s = get_next_keyspec ()))
     @{
       gpgrt_fputc ('\n', memfp);
       gpgrt_fputs (s, memfp);
     @}
   gpgrt_fputc (0, memfp);
   if (gpgrt_ferror (memfp))
     @{ perror ("writing to memstream failed"); exit (2); @}
   if (gpgrt_fclose_snatch (memfp, &result, NULL))
     @{ perror ("fclose_snatch failed"); exit (2); @}
   return result;
 @}
 @end example
 
 In this example @code{get_next_keyspec} is expected to return the next
 key to be added to the string.  Please take care: Encrypting to a
 large number of recipients is often questionable due to security
 reasons and also for the technicality that all keys are currently
 passed on the command line to @command{gpg} which has as a platform
 specific length limitation.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_ext_start @
             (@w{gpgme_ctx_t @var{ctx}}, @
              @w{gpgme_key_t @var{recp}[]}, @
              @w{const char *@var{recpstring}}, @
              @w{gpgme_encrypt_flags_t @var{flags}}, @
              @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 
 @since{1.11.0}
 
 This is an extended version of @code{gpgme_op_encrypt_start} with
 @var{recpstring} as additional parameter.  If @var{recp} is NULL and
 @var{recpstring} is not NULL, the latter is expected to be a linefeed
 delimited string with the set of key specifications.  In contrast to
 @var{recp} the keys are given directly as strings and there is no need
 to first create key objects.  The keys are passed verbatim to the
 backend engine.
 
 @end deftypefun
 
 @deftp {Data type} {gpgme_encrypt_result_t}
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_encrypt} operation.  After successfully encrypting
 data, you can retrieve the pointer to the result with
 @code{gpgme_op_encrypt_result}.  The structure contains the following
 members:
 
 @table @code
 @item gpgme_invalid_key_t invalid_recipients
 A linked list with information about all invalid keys for which
 the data could not be encrypted.
 @end table
 @end deftp
 
 @deftypefun gpgme_encrypt_result_t gpgme_op_encrypt_result (@w{gpgme_ctx_t @var{ctx}})
 The function @code{gpgme_op_encrypt_result} returns a
 @code{gpgme_encrypt_result_t} pointer to a structure holding the
 result of a @code{gpgme_op_encrypt} operation.  The pointer is only
 valid if the last operation on the context was a
 @code{gpgme_op_encrypt}, @code{gpgme_op_encrypt_start},
 @code{gpgme_op_sign} or @code{gpgme_op_sign_start} operation.  If this
 operation failed, this might be a @code{NULL} pointer.  The returned
 pointer is only valid until the next operation is started on the
 context.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_sign (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{recp}[]}, @w{gpgme_encrypt_flags_t @var{flags}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 The function @code{gpgme_op_encrypt_sign} does a combined encrypt and
 sign operation.  It is used like @code{gpgme_op_encrypt}, but the
 ciphertext also contains signatures for the signers listed in
 @var{ctx}.
 
 The combined encrypt and sign operation is currently only available
 for the OpenPGP crypto engine.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_sign_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{recp}[]}, @w{gpgme_encrypt_flags_t @var{flags}}, @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 The function @code{gpgme_op_encrypt_sign_start} initiates a
 @code{gpgme_op_encrypt_sign} operation.  It can be completed by
 calling @code{gpgme_wait} on the context.  @xref{Waiting For
 Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation could be started successfully, and @code{GPG_ERR_INV_VALUE}
 if @var{ctx}, @var{rset}, @var{plain} or @var{cipher} is not a valid
 pointer.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_sign_ext @
             (@w{gpgme_ctx_t @var{ctx}}, @
              @w{gpgme_key_t @var{recp}[]}, @
              @w{const char *@var{recpstring}}, @
              @w{gpgme_encrypt_flags_t @var{flags}}, @
              @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 
 @since{1.11.0}
 
 This is an extended version of @code{gpgme_op_encrypt_sign} with
 @var{recpstring} as additional parameter.  If @var{recp} is NULL and
 @var{recpstring} is not NULL, the latter is expected to be a linefeed
 delimited string with the set of key specifications.  In contrast to
 @var{recp} the keys are given directly as strings and there is no need
 to first create the key objects.  The keys are passed verbatim to the
 backend engine.
 
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_encrypt_sign_ext_start @
             (@w{gpgme_ctx_t @var{ctx}}, @
              @w{gpgme_key_t @var{recp}[]}, @
              @w{const char *@var{recpstring}}, @
              @w{gpgme_encrypt_flags_t @var{flags}}, @
              @w{gpgme_data_t @var{plain}}, @w{gpgme_data_t @var{cipher}})
 
 @since{1.11.0}
 
 This is an extended version of @code{gpgme_op_encrypt_sign_start} with
 @var{recpstring} as additional parameter.  If @var{recp} is NULL and
 @var{recpstring} is not NULL, the latter is expected to be a linefeed
 delimited string with the set of key specifications.  In contrast to
 @var{recp} the keys are given directly as strings and there is no need
 to first create the key objects.  The keys are passed verbatim to the
 backend engine.
 
 @end deftypefun
 
 
 @node Miscellaneous
 @section Miscellaneous operations
 
 Here are some support functions which are sometimes useful.
 
 @menu
 * Running other Programs::      Running other Programs
 * Using the Assuan protocol::   Using the Assuan protocol
 * Checking for updates::        How to check for software updates
 @end menu
 
 
 @node Running other Programs
 @subsection Running other Programs
 
 GPGME features an internal subsystem to run the actual backend
 engines.  Along with data abstraction object this subsystem can be
 used to run arbitrary simple programs which even need not be related
 to cryptographic features.  It may for example be used to run tools
 which are part of the GnuPG system but are not directly accessible
 with the GPGME API.
 
 
 @deftypefun gpgme_error_t gpgme_op_spawn @
             (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{file}}, @
              @w{const char *@var{argv}[]}, @w{gpgme_data_t @var{datain}}, @
              @w{gpgme_data_t @var{dataout}}, @w{gpgme_data_t @var{dataerr}}, @
              @w{unsigned int @var{flags}})
 
 @since{1.5.0}
 
 The function @code{gpgme_op_spawn} runs the program @var{file} with
 the arguments taken from the NULL terminated array @var{argv}.  If no
 arguments are required @var{argv} may be given as @code{NULL}.  In the
 latter case or if @code{argv[0]} is the empty string, GPGME uses the
 basename of @var{file} for @code{argv[0]}.  The file descriptors
 @code{stdin}, @code{stdout}, and @code{stderr} are connected to the
 data objects @var{datain}, @var{dataout}, and @var{dataerr}.  If NULL
 is passed for one of these data objects the corresponding file
 descriptor is connected to @file{/dev/null}.
 
 The value in @var{flags} is a bitwise-or combination of one or
 multiple of the following bit values:
 
 @table @code
 @item GPGME_SPAWN_DETACHED
 @since{1.5.0}
 
 Under Windows this flag inhibits the allocation of a new console for
 the program.  This is useful for a GUI application which needs to call
 a command line helper tool.
 
 @item GPGME_SPAWN_ALLOW_SET_FG
 @since{1.5.0}
 
 Under Windows this flag allows the called program to put itself into
 the foreground.
 @end table
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_spawn_start @
             (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{file}}, @
              @w{const char *@var{argv}[]}, @w{gpgme_data_t @var{datain}}, @
              @w{gpgme_data_t @var{dataout}}, @w{gpgme_data_t @var{dataerr}}, @
              @w{unsigned int @var{flags}})
 
 @since{1.5.0}
 
 This is the asynchronous variant of @code{gpgme_op_spawn}.
 @end deftypefun
 
 
 @node Using the Assuan protocol
 @subsection Using the Assuan protocol
 
 The Assuan protocol can be used to talk to arbitrary Assuan servers.
 By default it is connected to the GnuPG agent, but it may be connected
 to arbitrary servers by using @code{gpgme_ctx_set_engine_info},
 passing the location of the servers socket as @var{file_name}
 argument, and an empty string as @var{home_dir} argument.
 
 The Assuan protocol functions use three kinds of callbacks to transfer
 data:
 
 @deftp {Data type} {gpgme_error_t (*gpgme_assuan_data_cb_t) @
        (@w{void *@var{opaque}}, @w{const void *@var{data}}, @
         @w{size_t @var{datalen}})}
 
 @since{1.2.0}
 
 This callback receives any data sent by the server.  @var{opaque} is
 the pointer passed to @code{gpgme_op_assuan_transact_start},
 @var{data} of length @var{datalen} refers to the data sent.
 @end deftp
 
 @deftp {Data type} {gpgme_error_t (*gpgme_assuan_inquire_cb_t) @
        (@w{void *@var{opaque}}, @w{const char *@var{name}}, @
         @w{const char *@var{args}}, @w{gpgme_data_t *@var{r_data}})}
 
 @since{1.2.0}
 
 This callback is used to provide additional data to the Assuan server.
 @var{opaque} is the pointer passed to
 @code{gpgme_op_assuan_transact_start}, @var{name} and @var{args}
 specify what kind of data the server requested, and @var{r_data} is
 used to return the actual data.
 
 Note: Returning data is currently not implemented in @acronym{GPGME}.
 @end deftp
 
 @deftp {Data type} {gpgme_error_t (*gpgme_assuan_status_cb_t) @
        (@w{void *@var{opaque}}, @w{const char *@var{status}}, @
         @w{const char *@var{args}})}
 
 @since{1.2.0}
 
 This callback receives any status lines sent by the server.
 @var{opaque} is the pointer passed to
 @code{gpgme_op_assuan_transact_start}, @var{status} and @var{args}
 denote the status update sent.
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_op_assuan_transact_start @
             (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{command}}, @
              @w{gpgme_assuan_data_cb_t @var{data_cb}}, @
              @w{void * @var{data_cb_value}}, @
              @w{gpgme_assuan_inquire_cb_t @var{inquire_cb}}, @
              @w{void * @var{inquire_cb_value}}, @
              @w{gpgme_assuan_status_cb_t @var{status_cb}}, @
              @w{void * @var{status_cb_value}})
 
 @since{1.2.0}
 
 Send the Assuan @var{command} and return results via the callbacks.
 Any callback may be @code{NULL}.  The result of the operation may be
 retrieved using @code{gpgme_wait_ext}.
 
 Asynchronous variant.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_assuan_transact_ext @
             (@w{gpgme_ctx_t @var{ctx}}, @w{const char *@var{command}}, @
              @w{gpgme_assuan_data_cb_t @var{data_cb}}, @
              @w{void * @var{data_cb_value}}, @
              @w{gpgme_assuan_inquire_cb_t @var{inquire_cb}}, @
              @w{void * @var{inquire_cb_value}}, @
              @w{gpgme_assuan_status_cb_t @var{status_cb}}, @
              @w{void * @var{status_cb_value}}, @
              @w{gpgme_error_t *@var{op_err}})
 
 Send the Assuan @var{command} and return results via the callbacks.
 The result of the operation is returned in @var{op_err}.
 
 Synchronous variant.
 @end deftypefun
 
 
 @node Checking for updates
 @subsection How to check for software updates
 
 The GnuPG Project operates a server to query the current versions of
 software packages related to GnuPG.  GPGME can be used to
 access this online database and check whether a new version of a
 software package is available.
 
 @deftp {Data type} {gpgme_query_swdb_result_t}
 @since{1.8.0}
 
 This is a pointer to a structure used to store the result of a
 @code{gpgme_op_query_swdb} operation.  After success full call to that
 function, you can retrieve the pointer to the result with
 @code{gpgme_op_query_swdb_result}.  The structure contains the
 following member:
 
 @table @code
 @item name
 This is the name of the package.
 
 @item iversion
 The currently installed version or an empty string.  This value is
 either a copy of the argument given to @code{gpgme_op_query_swdb} or
 the version of the installed software as figured out by GPGME or GnuPG.
 
 @item created
 This gives the date the file with the list of version numbers has
 originally be created by the GnuPG project.
 
 @item retrieved
 This gives the date the file was downloaded.
 
 @item warning
 If this flag is set either an error has occurred or some of the
 information in this structure are not properly set.  For example if
 the version number of the installed software could not be figured out,
 the @code{update} flag may not reflect a required update status.
 
 @item update
 If this flag is set an update of the software is available.
 
 @item urgent
 If this flag is set an available update is important.
 
 @item noinfo
 If this flag is set, no valid information could be retrieved.
 
 @item unknown
 If this flag is set the given @code{name} is not known.
 
 @item tooold
 If this flag is set the available information is not fresh enough.
 
 @item error
 If this flag is set some other error has occurred.
 
 @item version
 The version string of the latest released version.
 
 @item reldate
 The release date of the latest released version.
 
 @end table
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_op_query_swdb @
             (@w{gpgme_ctx_t @var{ctx}},       @
              @w{const char *@var{name}},      @
              @w{const char *@var{iversion}},  @
              @w{gpgme_data_t @var{reserved}})
 
 @since{1.8.0}
 
 Query the software version database for software package @var{name}
 and check against the installed version given by @var{iversion}.  If
 @var{iversion} is given as @code{NULL} a check is only done if GPGME
 can figure out the version by itself (for example when using
 "gpgme" or "gnupg").  If @code{NULL} is used for @var{name} the
 current gpgme version is checked.  @var{reserved} must be set to 0.
 
 @end deftypefun
 
 @deftypefun gpgme_query_swdb_result_t gpgme_op_query_swdb_result @
             (@w{gpgme_ctx_t @var{ctx}})
 
 @since{1.8.0}
 
 The function @code{gpgme_op_query_swdb_result} returns a
 @code{gpgme_query_swdb_result_t} pointer to a structure holding the
 result of a @code{gpgme_op_query_swdb} operation.  The pointer is only
 valid if the last operation on the context was a successful call to
 @code{gpgme_op_query_swdb}.  If that call failed, the result might
 be a @code{NULL} pointer.  The returned pointer is only valid until
 the next operation is started on the context @var{ctx}.
 @end deftypefun
 
 @noindent
 Here is an example on how to check whether GnuPG is current:
 
 @example
 #include <gpgme.h>
 
 int
 main (void)
 @{
   gpg_error_t err;
   gpgme_ctx_t ctx;
   gpgme_query_swdb_result_t result;
 
   gpgme_check_version (NULL);
   err = gpgme_new (&ctx);
   if (err)
     fprintf (stderr, "error creating context: %s\n", gpg_strerror (err));
   else
     @{
       gpgme_set_protocol (ctx, GPGME_PROTOCOL_GPGCONF);
 
       err = gpgme_op_query_swdb (ctx, "gnupg", NULL, 0);
       if (err)
         fprintf (stderr, "error querying swdb: %s\n", gpg_strerror (err));
       else
         @{
           result = gpgme_op_query_swdb_result (ctx);
           if (!result)
             fprintf (stderr, "error querying swdb\n");
           if (!result->warning && !result->update)
             printf ("GnuPG version %s is current\n",
                     result->iversion);
           else if (!result->warning && result->update)
             printf ("GnuPG version %s can be updated to %s\n",
                     result->iversion, result->version);
           else
             fprintf (stderr, "error finding the update status\n");
         @}
       gpgme_release (ctx);
     @}
   return 0;
 @}
 @end example
 
 
 @node Run Control
 @section Run Control
 @cindex run control
 @cindex cryptographic operation, running
 
 @acronym{GPGME} supports running operations synchronously and
 asynchronously.  You can use asynchronous operation to set up a
 context up to initiating the desired operation, but delay performing
 it to a later point.
 
 Furthermore, you can use an external event loop to control exactly
 when @acronym{GPGME} runs.  This ensures that @acronym{GPGME} only
 runs when necessary and also prevents it from blocking for a long
 time.
 
 @menu
 * Waiting For Completion::        Waiting until an operation is completed.
 * Using External Event Loops::    Advanced control over what happens when.
 * Cancellation::                  How to end pending operations prematurely.
 @end menu
 
 
 @node Waiting For Completion
 @subsection Waiting For Completion
 @cindex cryptographic operation, wait for
 @cindex wait for completion
 
 @deftypefun gpgme_ctx_t gpgme_wait (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_error_t *@var{status}}, @w{int @var{hang}})
 The function @code{gpgme_wait} continues the pending operation within
 the context @var{ctx}.  In particular, it ensures the data exchange
 between @acronym{GPGME} and the crypto backend and watches over the
 run time status of the backend process.
 
 If @var{hang} is true, the function does not return until the
 operation is completed or cancelled.  Otherwise the function will not
 block for a long time.
 
 The error status of the finished operation is returned in @var{status}
 if @code{gpgme_wait} does not return @code{NULL}.
 
 The @var{ctx} argument can be @code{NULL}.  In that case,
 @code{gpgme_wait} waits for any context to complete its operation.
 
 @code{gpgme_wait} can be used only in conjunction with any context
 that has a pending operation initiated with one of the
 @code{gpgme_op_*_start} functions except @code{gpgme_op_keylist_start}
 and @code{gpgme_op_trustlist_start} (for which you should use the
 corresponding @code{gpgme_op_*_next} functions).  If @var{ctx} is
 @code{NULL}, all of such contexts are waited upon and possibly
 returned.  Synchronous operations running in parallel, as well as key
 and trust item list operations, do not affect @code{gpgme_wait}.
 
 In a multi-threaded environment, only one thread should ever call
 @code{gpgme_wait} at any time, regardless of whether @var{ctx} is specified
 or not.  This means that all calls to this function should be fully
 synchronized by locking primitives.  It is safe to start asynchronous
 operations while a thread is running in @code{gpgme_wait}.
 
 The function returns the @var{ctx} of the context which has finished
 the operation.  If @var{hang} is false, and the timeout expires,
 @code{NULL} is returned and @code{*status} will be set to 0.  If an
 error occurs, @code{NULL} is returned and the error is returned in
 @code{*status}.
 @end deftypefun
 
 
 @node Using External Event Loops
 @subsection Using External Event Loops
 @cindex event loop, external
 
 @acronym{GPGME} hides the complexity of the communication between the
 library and the crypto engine.  The price of this convenience is that
 the calling thread can block arbitrary long waiting for the data
 returned by the crypto engine.  In single-threaded programs, in
 particular if they are interactive, this is an unwanted side-effect.
 OTOH, if @code{gpgme_wait} is used without the @var{hang} option being
 enabled, it might be called unnecessarily often, wasting CPU time that
 could be used otherwise.
 
 The I/O callback interface described in this section lets the user
 take control over what happens when.  @acronym{GPGME} will provide the
 user with the file descriptors that should be monitored, and the
 callback functions that should be invoked when a file descriptor is
 ready for reading or writing.  It is then the user's responsibility to
 decide when to check the file descriptors and when to invoke the
 callback functions.  Usually this is done in an event loop, that also
 checks for events in other parts of the program.  If the callback
 functions are only called when the file descriptors are ready,
 @acronym{GPGME} will never block.  This gives the user more control
 over the program flow, and allows to perform other tasks when
 @acronym{GPGME} would block otherwise.
 
 By using this advanced mechanism, @acronym{GPGME} can be integrated
 smoothly into GUI toolkits like GTK+ even for single-threaded
 programs.
 
 @menu
 * I/O Callback Interface::        How I/O callbacks are registered.
 * Registering I/O Callbacks::     How to use I/O callbacks for a context.
 * I/O Callback Example::          An example how to use I/O callbacks.
 * I/O Callback Example GTK+::     How to use @acronym{GPGME} with GTK+.
 * I/O Callback Example GDK::      How to use @acronym{GPGME} with GDK.
 * I/O Callback Example Qt::       How to use @acronym{GPGME} with Qt.
 @end menu
 
 
 @node I/O Callback Interface
 @subsubsection I/O Callback Interface
 
 @deftp {Data type} {gpgme_error_t (*gpgme_io_cb_t) (@w{void *@var{data}}, @w{int @var{fd}})}
 @tindex gpgme_io_cb_t
 The @code{gpgme_io_cb_t} type is the type of functions which
 @acronym{GPGME} wants to register as I/O callback handlers using the
 @code{gpgme_register_io_cb_t} functions provided by the user.
 
 @var{data} and @var{fd} are provided by @acronym{GPGME} when the I/O
 callback handler is registered, and should be passed through to the
 handler when it is invoked by the user because it noticed activity on
 the file descriptor @var{fd}.
 
 The callback handler always returns @code{0}, but you should consider
 the return value to be reserved for later use.
 @end deftp
 
 @deftp {Data type} {gpgme_error_t (*gpgme_register_io_cb_t) (@w{void *@var{data}}, @w{int @var{fd}}, @w{int @var{dir}}, @w{gpgme_io_cb_t @var{fnc}}, @w{void *@var{fnc_data}}, @w{void **@var{tag}})}
 @tindex gpgme_register_io_cb_t
 The @code{gpgme_register_io_cb_t} type is the type of functions which can
 be called by @acronym{GPGME} to register an I/O callback function
 @var{fnc} for the file descriptor @var{fd} with the user.
 @var{fnc_data} should be passed as the first argument to @var{fnc}
 when the handler is invoked (the second argument should be @var{fd}).
 If @var{dir} is 0, @var{fnc} should be called by the user when
 @var{fd} is ready for writing.  If @var{dir} is 1, @var{fnc} should be
 called when @var{fd} is ready for reading.
 
 @var{data} was provided by the user when registering the
 @code{gpgme_register_io_cb_t} function with @acronym{GPGME} and will always
 be passed as the first argument when registering a callback function.
 For example, the user can use this to determine the event loop to
 which the file descriptor should be added.
 
 @acronym{GPGME} will call this function when a crypto operation is
 initiated in a context for which the user has registered I/O callback
 handler functions with @code{gpgme_set_io_cbs}.  It can also call this
 function when it is in an I/O callback handler for a file descriptor
 associated to this context.
 
 The user should return a unique handle in @var{tag} identifying this
 I/O callback registration, which will be passed to the
 @code{gpgme_register_io_cb_t} function without interpretation when the file
 descriptor should not be monitored anymore.
 @end deftp
 
 @deftp {Data type} {void (*gpgme_remove_io_cb_t) (@w{void *@var{tag}})}
 The @code{gpgme_remove_io_cb_t} type is the type of functions which can be
 called by @acronym{GPGME} to remove an I/O callback handler that was
 registered before.  @var{tag} is the handle that was returned by the
 @code{gpgme_register_io_cb_t} for this I/O callback.
 
 @acronym{GPGME} can call this function when a crypto operation is in
 an I/O callback.  It will also call this function when the context is
 destroyed while an operation is pending.
 @end deftp
 
 @deftp {Data type} {enum gpgme_event_io_t}
 @tindex gpgme_event_io_t
 The @code{gpgme_event_io_t} type specifies the type of an event that is
 reported to the user by @acronym{GPGME} as a consequence of an I/O
 operation.  The following events are defined:
 
 @table @code
 @item GPGME_EVENT_START
 The operation is fully initialized now, and you can start to run the
 registered I/O callback handlers now.  Note that registered I/O
 callback handlers must not be run before this event is signalled.
 @var{type_data} is @code{NULL} and reserved for later use.
 
 @item GPGME_EVENT_DONE
 The operation is finished, the last I/O callback for this operation
 was removed.  The accompanying @var{type_data} points to a
 @code{struct gpgme_io_event_done_data} variable that contains the
 status of the operation that finished.  This event is signalled after
 the last I/O callback has been removed.
 
 @item GPGME_EVENT_NEXT_KEY
 In a @code{gpgme_op_keylist_start} operation, the next key was
 received from the crypto engine.  The accompanying @var{type_data} is
 a @code{gpgme_key_t} variable that contains the key with one reference
 for the user.
 
 @end table
 @end deftp
 
 @deftp {Data type} {void (*gpgme_event_io_cb_t) (@w{void *@var{data}}, @w{gpgme_event_io_t @var{type}}, @w{void *@var{type_data}})}
 The @code{gpgme_event_io_cb_t} type is the type of functions which can be
 called by @acronym{GPGME} to signal an event for an operation running
 in a context which has I/O callback functions registered by the user.
 
 @var{data} was provided by the user when registering the
 @code{gpgme_event_io_cb_t} function with @acronym{GPGME} and will always be
 passed as the first argument when registering a callback function.
 For example, the user can use this to determine the context in which
 this event has occurred.
 
 @var{type} will specify the type of event that has occurred.
 @var{type_data} specifies the event further, as described in the above
 list of possible @code{gpgme_event_io_t} types.
 
 @acronym{GPGME} can call this function in an I/O callback handler.
 @end deftp
 
 
 @node Registering I/O Callbacks
 @subsubsection Registering I/O Callbacks
 
 @deftp {Data type} {struct gpgme_io_cbs}
 @tindex gpgme_event_io_t
 This structure is used to store the I/O callback interface functions
 described in the previous section.  It has the following members:
 
 @table @code
 @item gpgme_register_io_cb_t add
 This is the function called by @acronym{GPGME} to register an I/O
 callback handler.  It must be specified.
 
 @item void *add_priv
 This is passed as the first argument to the @code{add} function when
 it is called by @acronym{GPGME}.  For example, it can be used to
 determine the event loop to which the file descriptor should be added.
 
 @item gpgme_remove_io_cb_t remove
 This is the function called by @acronym{GPGME} to remove an I/O
 callback handler.  It must be specified.
 
 @item gpgme_event_io_cb_t event
 This is the function called by @acronym{GPGME} to signal an event for
 an operation.  It must be specified, because at least the start event
 must be processed.
 
 @item void *event_priv
 This is passed as the first argument to the @code{event} function when
 it is called by @acronym{GPGME}.  For example, it can be used to
 determine the context in which the event has occurred.
 @end table
 @end deftp
 
 @deftypefun void gpgme_set_io_cbs (@w{gpgme_ctx_t @var{ctx}}, @w{struct gpgme_io_cbs *@var{io_cbs}})
 The function @code{gpgme_set_io_cbs} enables the I/O callback
 interface for the context @var{ctx}.  The I/O callback functions are
 specified by @var{io_cbs}.
 
 If @var{io_cbs}->@code{add} is @code{NULL}, the I/O callback interface
 is disabled for the context, and normal operation is restored.
 @end deftypefun
 
 @deftypefun void gpgme_get_io_cbs (@w{gpgme_ctx_t @var{ctx}}, @w{struct gpgme_io_cbs *@var{io_cbs}})
 The function @code{gpgme_get_io_cbs} returns the I/O callback
 functions set with @code{gpgme_set_io_cbs} in @var{io_cbs}.
 @end deftypefun
 
 
 @node I/O Callback Example
 @subsubsection I/O Callback Example
 
 To actually use an external event loop, you have to implement the I/O
 callback functions that are used by @acronym{GPGME} to register and
 unregister file descriptors.  Furthermore, you have to actually
 monitor these file descriptors for activity and call the appropriate
 I/O callbacks.
 
 The following example illustrates how to do that.  The example uses
 locking to show in which way the callbacks and the event loop can
 run concurrently.  For the event loop, we use a fixed array.  For a
 real-world implementation, you should use a dynamically sized
 structure because the number of file descriptors needed for a crypto
 operation in @acronym{GPGME} is not predictable.
 
 @example
 #include <assert.h>
 #include <errno.h>
 #include <stdlib.h>
 #include <pthread.h>
 #include <sys/types.h>
 #include <gpgme.h>
 
 /* The following structure holds the result of a crypto operation.  */
 struct op_result
 @{
   int done;
   gpgme_error_t err;
 @};
 
 /* The following structure holds the data associated with one I/O
 callback.  */
 struct one_fd
 @{
   int fd;
   int dir;
   gpgme_io_cb_t fnc;
   void *fnc_data;
   void *loop;
 @};
 
 struct event_loop
 @{
   pthread_mutex_t lock;
 #define MAX_FDS 32
   /* Unused slots are marked with FD being -1.  */
   struct one_fd fds[MAX_FDS];
 @};
 @end example
 
 The following functions implement the I/O callback interface.
 
 @example
 gpgme_error_t
 add_io_cb (void *data, int fd, int dir, gpgme_io_cb_t fnc, void *fnc_data,
 	   void **r_tag)
 @{
   struct event_loop *loop = data;
   struct one_fd *fds = loop->fds;
   int i;
 
   pthread_mutex_lock (&loop->lock);
   for (i = 0; i < MAX_FDS; i++)
     @{
       if (fds[i].fd == -1)
 	@{
 	  fds[i].fd = fd;
 	  fds[i].dir = dir;
 	  fds[i].fnc = fnc;
 	  fds[i].fnc_data = fnc_data;
 	  fds[i].loop = loop;
 	  break;
 	@}
     @}
   pthread_mutex_unlock (&loop->lock);
   if (i == MAX_FDS)
     return gpg_error (GPG_ERR_GENERAL);
   *r_tag = &fds[i];
   return 0;
 @}
 
 void
 remove_io_cb (void *tag)
 @{
   struct one_fd *fd = tag;
   struct event_loop *loop = fd->loop;
 
   pthread_mutex_lock (&loop->lock);
   fd->fd = -1;
   pthread_mutex_unlock (&loop->lock);
 @}
 
 void
 event_io_cb (void *data, gpgme_event_io_t type, void *type_data)
 @{
   struct op_result *result = data;
 
   /* We don't support list operations here.  */
   if (type == GPGME_EVENT_DONE)
     @{
       result->done = 1;
       result->err = *type_data;
     @}
 @}
 @end example
 
 The final missing piece is the event loop, which will be presented
 next.  We only support waiting for the success of a single operation.
 
 @example
 int
 do_select (struct event_loop *loop)
 @{
   fd_set rfds;
   fd_set wfds;
   int i, n;
   int any = 0;
   struct timeval tv;
   struct one_fd *fdlist = loop->fds;
 
   pthread_mutex_lock (&loop->lock);
   FD_ZERO (&rfds);
   FD_ZERO (&wfds);
   for (i = 0; i < MAX_FDS; i++)
     if (fdlist[i].fd != -1)
       FD_SET (fdlist[i].fd, fdlist[i].dir ? &rfds : &wfds);
   pthread_mutex_unlock (&loop->lock);
 
   tv.tv_sec = 0;
   tv.tv_usec = 1000;
 
   do
     @{
       n = select (FD_SETSIZE, &rfds, &wfds, NULL, &tv);
     @}
   while (n < 0 && errno == EINTR);
 
   if (n < 0)
     return n;	/* Error or timeout.  */
 
   pthread_mutex_lock (&loop->lock);
   for (i = 0; i < MAX_FDS && n; i++)
     @{
       if (fdlist[i].fd != -1)
 	@{
 	  if (FD_ISSET (fdlist[i].fd, fdlist[i].dir ? &rfds : &wfds))
 	    @{
 	      assert (n);
 	      n--;
 	      any = 1;
               /* The I/O callback handler can register/remove callbacks,
                  so we have to unlock the file descriptor list.  */
               pthread_mutex_unlock (&loop->lock);
 	      (*fdlist[i].fnc) (fdlist[i].fnc_data, fdlist[i].fd);
               pthread_mutex_lock (&loop->lock);
 	    @}
 	@}
     @}
   pthread_mutex_unlock (&loop->lock);
   return any;
 @}
 
 void
 wait_for_op (struct event_loop *loop, struct op_result *result)
 @{
   int ret;
 
   do
     @{
       ret = do_select (loop);
     @}
   while (ret >= 0 && !result->done);
 @}
 @end example
 
 The main function shows how to put it all together.
 
 @example
 int
 main (int argc, char *argv[])
 @{
   struct event_loop loop;
   struct op_result result;
   gpgme_ctx_t ctx;
   gpgme_error_t err;
   gpgme_data_t sig, text;
   int i;
   pthread_mutexattr_t attr;
   struct gpgme_io_cbs io_cbs =
   @{
     add_io_cb,
     &loop,
     remove_io_cb,
     event_io_cb,
     &result
   @};
 
   init_gpgme ();
 
   /* Initialize the loop structure.  */
 
   /* The mutex must be recursive, since remove_io_cb (which acquires a
      lock) can be called while holding a lock acquired in do_select.  */
   pthread_mutexattr_init (&attr);
   pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
   pthread_mutex_init (&loop.lock, &attr);
   pthread_mutexattr_destroy (&attr);
 
   for (i = 0; i < MAX_FDS; i++)
     loop.fds[i].fd = -1;
 
   /* Initialize the result structure.  */
   result.done = 0;
 
   err = gpgme_data_new_from_file (&sig, "signature", 1);
   if (!err)
     err = gpgme_data_new_from_file (&text, "text", 1);
   if (!err)
     err = gpgme_new (&ctx);
   if (!err)
     @{
        gpgme_set_io_cbs (ctx, &io_cbs);
        err = gpgme_op_verify_start (ctx, sig, text, NULL);
     @}
   if (err)
     @{
       fprintf (stderr, "gpgme error: %s: %s\n",
                gpgme_strsource (err), gpgme_strerror (err));
       exit (1);
     @}
 
   wait_for_op (&loop, &result);
   if (!result.done)
     @{
       fprintf (stderr, "select error\n");
       exit (1);
     @}
   if (!result.err)
     @{
       fprintf (stderr, "verification failed: %s: %s\n",
                gpgme_strsource (result.err), gpgme_strerror (result.err));
       exit (1);
     @}
   /* Evaluate verify result.  */
   @dots{}
   return 0;
 @}
 @end example
 
 
 @node I/O Callback Example GTK+
 @subsubsection I/O Callback Example GTK+
 @cindex GTK+, using @acronym{GPGME} with
 
 The I/O callback interface can be used to integrate @acronym{GPGME}
 with the GTK+ event loop.  The following code snippets shows how this
 can be done using the appropriate register and remove I/O callback
 functions.  In this example, the private data of the register I/O
 callback function is unused.  The event notifications is missing
 because it does not require any GTK+ specific setup.
 
 @example
 #include <gtk/gtk.h>
 
 struct my_gpgme_io_cb
 @{
   gpgme_io_cb_t fnc;
   void *fnc_data;
   guint input_handler_id
 @};
 
 void
 my_gpgme_io_cb (gpointer data, gint source, GdkInputCondition condition)
 @{
   struct my_gpgme_io_cb *iocb = data;
   (*(iocb->fnc)) (iocb->data, source);
 @}
 
 void
 my_gpgme_remove_io_cb (void *data)
 @{
   struct my_gpgme_io_cb *iocb = data;
   gtk_input_remove (data->input_handler_id);
 @}
 
 void
 my_gpgme_register_io_callback (void *data, int fd, int dir, gpgme_io_cb_t fnc,
                                void *fnc_data, void **tag)
 @{
   struct my_gpgme_io_cb *iocb = g_malloc (sizeof (struct my_gpgme_io_cb));
   iocb->fnc = fnc;
   iocb->data = fnc_data;
   iocb->input_handler_id = gtk_input_add_full (fd, dir
                                                    ? GDK_INPUT_READ
                                                    : GDK_INPUT_WRITE,
                                                my_gpgme_io_callback,
                                                0, iocb, NULL);
   *tag = iocb;
   return 0;
 @}
 @end example
 
 
 @node I/O Callback Example GDK
 @subsubsection I/O Callback Example GDK
 @cindex GDK, using @acronym{GPGME} with
 
 The I/O callback interface can also be used to integrate
 @acronym{GPGME} with the GDK event loop.  The following code snippets
 shows how this can be done using the appropriate register and remove
 I/O callback functions.  In this example, the private data of the
 register I/O callback function is unused.  The event notifications is
 missing because it does not require any GDK specific setup.
 
 It is very similar to the GTK+ example in the previous section.
 
 @example
 #include <gdk/gdk.h>
 
 struct my_gpgme_io_cb
 @{
   gpgme_io_cb_t fnc;
   void *fnc_data;
   gint tag;
 @};
 
 void
 my_gpgme_io_cb (gpointer data, gint source, GdkInputCondition condition)
 @{
   struct my_gpgme_io_cb *iocb = data;
   (*(iocb->fnc)) (iocb->data, source);
 @}
 
 void
 my_gpgme_remove_io_cb (void *data)
 @{
   struct my_gpgme_io_cb *iocb = data;
   gdk_input_remove (data->tag);
 @}
 
 void
 my_gpgme_register_io_callback (void *data, int fd, int dir, gpgme_io_cb_t fnc,
                                void *fnc_data, void **tag)
 @{
   struct my_gpgme_io_cb *iocb = g_malloc (sizeof (struct my_gpgme_io_cb));
   iocb->fnc = fnc;
   iocb->data = fnc_data;
   iocb->tag = gtk_input_add_full (fd, dir ? GDK_INPUT_READ : GDK_INPUT_WRITE,
                                   my_gpgme_io_callback, iocb, NULL);
   *tag = iocb;
   return 0;
 @}
 @end example
 
 
 @node I/O Callback Example Qt
 @subsubsection I/O Callback Example Qt
 @cindex Qt, using @acronym{GPGME} with
 
 The I/O callback interface can also be used to integrate
 @acronym{GPGME} with the Qt event loop.  The following code snippets
 show how this can be done using the appropriate register and remove
 I/O callback functions.  In this example, the private data of the
 register I/O callback function is unused.  The event notifications is
 missing because it does not require any Qt specific setup.
 
 @example
 #include <qsocketnotifier.h>
 #include <qapplication.h>
 
 struct IOCB @{
   IOCB( GpgmeIOCb f, void * d, QSocketNotifier * n )
     : func( f ), data( d ), notifier( n ) @{@}
   GpgmeIOCb func;
   void * data;
   QSocketNotifier * notifier;
 @}
 
 class MyApp : public QApplication @{
 
   // ...
 
   static void registerGpgmeIOCallback( void * data, int fd, int dir,
                                        GpgmeIOCb func, void * func_data,
                                        void ** tag ) @{
     QSocketNotifier * n =
       new QSocketNotifier( fd, dir ? QSocketNotifier::Read
                                    : QSocketNotifier::Write );
     connect( n, SIGNAL(activated(int)),
              qApp, SLOT(slotGpgmeIOCallback(int)) );
     qApp->mIOCBs.push_back( IOCB( func, func_data, n ) );
     *tag = (void*)n;
   @}
 
   static void removeGpgmeIOCallback( void * tag ) @{
     if ( !tag ) return;
     QSocketNotifier * n = static_cast<QSocketNotifier*>( tag );
     for ( QValueList<IOCB>::iterator it = qApp->mIOCBs.begin() ;
           it != qApp->mIOCBs.end() ; ++it )
       if ( it->notifier == n ) @{
         delete it->notifier;
         qApp->mIOCBs.erase( it );
         return;
       @}
   @}
 
 public slots:
   void slotGpgmeIOCallback( int fd ) @{
     for ( QValueList<IOCB>::const_iterator it = mIOCBs.begin() ;
           it != mIOCBs.end() ; ++it )
       if ( it->notifier && it->notifier->socket() == fd )
         (*(it->func)) ( it->func_data, fd );
   @}
 
   // ...
 
 private:
   QValueList<IOCB> mIOCBs;
   // ...
 @};
 @end example
 
 
 @node Cancellation
 @subsection Cancellation
 @cindex cryptographic operation, aborting
 @cindex cryptographic operation, cancelling
 @cindex aborting operations
 @cindex cancelling operations
 
 Sometimes you do not want to wait for an operation to finish.
 @acronym{GPGME} provides two different functions to achieve that.  The
 function @code{gpgme_cancel} takes effect immediately.  When it
 returns, the operation is effectively canceled.  However, it has some
 limitations and can not be used with synchronous operations.  In
 contrast, the function @code{gpgme_cancel_async} can be used with any
 context and from any thread, but it is not guaranteed to take effect
 immediately.  Instead, cancellation occurs at the next possible time
 (typically the next time I/O occurs in the target context).
 
 @deftypefun gpgme_ctx_t gpgme_cancel (@w{gpgme_ctx_t @var{ctx}})
 @since{0.4.5}
 
 The function @code{gpgme_cancel} attempts to cancel a pending
 operation in the context @var{ctx}.  This only works if you use the
 global event loop or your own event loop.
 
 If you use the global event loop, you must not call @code{gpgme_wait}
 during cancellation.  After successful
 cancellation, you can call @code{gpgme_wait} (optionally waiting on
 @var{ctx}), and the context @var{ctx} will appear as if it had
 finished with the error code @code{GPG_ERR_CANCEL}.
 
 If you use an external event loop, you must ensure that no I/O
 callbacks are invoked for this context (for example by halting the
 event loop).  On successful cancellation, all registered I/O callbacks
 for this context will be unregistered, and a @code{GPGME_EVENT_DONE}
 event with the error code @code{GPG_ERR_CANCEL} will be signalled.
 
 The function returns an error code if the cancellation failed (in this
 case the state of @var{ctx} is not modified).
 @end deftypefun
 
 
 @deftypefun gpgme_ctx_t gpgme_cancel_async (@w{gpgme_ctx_t @var{ctx}})
 @since{1.1.7}
 
 The function @code{gpgme_cancel_async} attempts to cancel a pending
 operation in the context @var{ctx}.  This can be called by any thread
 at any time after starting an operation on the context, but will not
 take effect immediately.  The actual cancellation happens at the next
 time GPGME processes I/O in that context.
 
 The function returns an error code if the cancellation failed (in this
 case the state of @var{ctx} is not modified).
 @end deftypefun
 
 @c **********************************************************
 @c *******************  Appendices  *************************
 @c **********************************************************
 
 @include uiserver.texi
 
 @node Debugging
 @appendix How to solve problems
 @cindex debug
 @cindex GPGME_DEBUG
 
 Everyone knows that software often does not do what it should do and thus
 there is a need to track down problems.  This is in particular true
 for applications using a complex library like @acronym{GPGME} and of
 course also for the library itself.  Here we give a few hints on how
 to solve such problems.
 
 First of all you should make sure that the keys you want to use are
 installed in the GnuPG engine and are usable.  Thus the first test is
 to run the desired operation using @command{gpg} or @command{gpgsm} on
 the command line.  If you can't figure out why things don't work, you
 may use @acronym{GPGME}'s built in trace feature.  This feature is
 either enabled using the environment variable @code{GPGME_DEBUG} or,
 if this is not possible, by calling the function
 @code{gpgme_set_global_flag}.  The value is the trace level and
 an optional file name.  If no file name is given the trace output is
 printed to @code{stderr}.
 
 @noindent
 For example
 @smallexample
 GPGME_DEBUG=9:/home/user/mygpgme.log
 @end smallexample
 @noindent
 (Note that under Windows you use a semicolon in place of the colon to
 separate the fields.)
 
 A trace level of 9 is pretty verbose and thus you may want to start
 off with a lower level.  The exact definition of the trace levels and
 the output format may change with any release; you need to check the
 source code for details.  In any case the trace log should be helpful
 to understand what is going going on.  Warning: The trace log may
 reveal sensitive details like passphrases or other data you use in
 your application.  If you are asked to send a log file, make sure that
 you run your tests only with play data.
 
 
 @node Deprecated Functions
 @appendix Deprecated Functions
 @cindex deprecated
 
 For backward compatibility @acronym{GPGME} has a number of functions,
 data types and constants which are deprecated and should not be used
 anymore.  We document here those which are really old to help
 understanding old code and to allow migration to their modern
 counterparts.
 
 @strong{Warning:} These interfaces will be removed in a future version
 of @acronym{GPGME}.
 
 @deftypefun void gpgme_key_release (@w{gpgme_key_t @var{key}})
 The function @code{gpgme_key_release} is equivalent to
 @code{gpgme_key_unref}.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_import_ext (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_data_t @var{keydata}}, @w{int *@var{nr}})
 @since{0.3.9}
 
 The function @code{gpgme_op_import_ext} is equivalent to:
 
 @example
   gpgme_error_t err = gpgme_op_import (ctx, keydata);
   if (!err)
     @{
       gpgme_import_result_t result = gpgme_op_import_result (ctx);
       *nr = result->considered;
     @}
 @end example
 @end deftypefun
 
 
 @deftp {Data type} {gpgme_error_t (*gpgme_edit_cb_t) @
    (@w{void *@var{handle}}, @
     @w{gpgme_status_code_t @var{status}}, @
     @w{const char *@var{args}}, @
     @w{int @var{fd}})}
 @tindex gpgme_edit_cb_t
 The @code{gpgme_edit_cb_t} type is the type of functions which
 @acronym{GPGME} calls if it a key edit operation is on-going.  The
 status code @var{status} and the argument line @var{args} are passed
 through by @acronym{GPGME} from the crypto engine.  The file
 descriptor @var{fd} is -1 for normal status messages.  If @var{status}
 indicates a command rather than a status message, the response to the
 command should be written to @var{fd}.  The @var{handle} is provided
 by the user at start of operation.
 
 The function should return @code{GPG_ERR_FALSE} if it did not handle
 the status code, @code{0} for success, or any other error value.
 @end deftp
 
 @deftypefun gpgme_error_t gpgme_op_edit (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{key}}, @w{gpgme_edit_cb_t @var{fnc}}, @w{void *@var{handle}}, @w{gpgme_data_t @var{out}})
 @since{0.3.9}
 
 Note: This function is deprecated, please use
 @code{gpgme_op_interact} instead.
 
 The function @code{gpgme_op_edit} processes the key @var{KEY}
 interactively, using the edit callback function @var{FNC} with the
 handle @var{HANDLE}.  The callback is invoked for every status and
 command request from the crypto engine.  The output of the crypto
 engine is written to the data object @var{out}.
 
 Note that the protocol between the callback function and the crypto
 engine is specific to the crypto engine and no further support in
 implementing this protocol correctly is provided by @acronym{GPGME}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 edit operation completes successfully, @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{key} is not a valid pointer, and any error returned
 by the crypto engine or the edit callback handler.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_edit_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{key}}, @w{gpgme_edit_cb_t @var{fnc}}, @w{void *@var{handle}}, @w{gpgme_data_t @var{out}})
 
 @since{0.3.9}
 
 Note: This function is deprecated, please use
 @code{gpgme_op_interact_start} instead.
 
 The function @code{gpgme_op_edit_start} initiates a
 @code{gpgme_op_edit} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation was started successfully, and @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{key} is not a valid pointer.
 @end deftypefun
 
 
 @deftypefun gpgme_error_t gpgme_op_card_edit (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{key}}, @w{gpgme_edit_cb_t @var{fnc}}, @w{void *@var{handle}}, @w{gpgme_data_t @var{out}})
 Note: This function is deprecated, please use @code{gpgme_op_interact}
 with the flag @code{GPGME_INTERACT_CARD} instead.
 
 The function @code{gpgme_op_card_edit} is analogous to
 @code{gpgme_op_edit}, but should be used to process the smart card corresponding to the key @var{key}.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_op_card_edit_start (@w{gpgme_ctx_t @var{ctx}}, @w{gpgme_key_t @var{key}}, @w{gpgme_edit_cb_t @var{fnc}}, @w{void *@var{handle}}, @w{gpgme_data_t @var{out}})
 Note: This function is deprecated, please use @code{gpgme_op_interact_start}
 with the flag @code{GPGME_INTERACT_CARD} instead.
 
 The function @code{gpgme_op_card_edit_start} initiates a
 @code{gpgme_op_card_edit} operation.  It can be completed by calling
 @code{gpgme_wait} on the context.  @xref{Waiting For Completion}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 operation was started successfully, and @code{GPG_ERR_INV_VALUE} if
 @var{ctx} or @var{key} is not a valid pointer.
 @end deftypefun
 
 
 
 @deftypefun gpgme_error_t gpgme_data_new_with_read_cb (@w{gpgme_data_t *@var{dh}}, @w{int (*@var{readfunc})} (@w{void *@var{hook}}, @w{char *@var{buffer}}, @w{size_t @var{count}}, @w{size_t *@var{nread}}), @w{void *@var{hook_value}})
 The function @code{gpgme_data_new_with_read_cb} creates a new
 @code{gpgme_data_t} object and uses the callback function @var{readfunc}
 to retrieve the data on demand.  As the callback function can supply
 the data in any way it wants, this is the most flexible data type
 @acronym{GPGME} provides.  However, it can not be used to write data.
 
 The callback function receives @var{hook_value} as its first argument
 whenever it is invoked.  It should return up to @var{count} bytes in
 @var{buffer}, and return the number of bytes actually read in
 @var{nread}.  It may return @code{0} in @var{nread} if no data is
 currently available.  To indicate @code{EOF} the function should
 return with an error code of @code{-1} and set @var{nread} to
 @code{0}.  The callback function may support to reset its internal
 read pointer if it is invoked with @var{buffer} and @var{nread} being
 @code{NULL} and @var{count} being @code{0}.
 
 The function returns the error code @code{GPG_ERR_NO_ERROR} if the
 data object was successfully created, @code{GPG_ERR_INV_VALUE} if
 @var{dh} or @var{readfunc} is not a valid pointer, and
 @code{GPG_ERR_ENOMEM} if not enough memory is available.
 @end deftypefun
 
 @deftypefun gpgme_error_t gpgme_data_rewind (@w{gpgme_data_t @var{dh}})
 The function @code{gpgme_data_rewind} is equivalent to:
 
 @example
   return (gpgme_data_seek (dh, 0, SEEK_SET) == -1)
     ? gpgme_error_from_errno (errno) : 0;
 @end example
 @end deftypefun
 
 
 @deftp {Data type} gpgme_attr_t
 The @code{gpgme_attr_t} type is used to specify a key or trust item
 attribute.  The following attributes are defined:
 
 @table @code
 @item GPGME_ATTR_KEYID
 This is the key ID of a sub key.  It is representable as a string.
 
 @item GPGME_ATTR_FPR
 This is the fingerprint of a sub key.  It is representable as a
 string.
 
 @item GPGME_ATTR_ALGO
 This is the crypto algorithm for which the sub key can be used.  It
 is representable as a string and as a number.  The numbers correspond
 to the @code{enum gcry_pk_algos} values in the gcrypt library.
 
 @item GPGME_ATTR_LEN
 This is the key length of a sub key.  It is representable as a
 number.
 
 @item GPGME_ATTR_CREATED
 This is the timestamp at creation time of a sub key.  It is
 representable as a number.
 
 @item GPGME_ATTR_EXPIRE
 This is the expiration time of a sub key.  It is representable as a
 number.
 
 @item GPGME_ATTR_USERID
 This is a user ID.  There can be more than one user IDs in a
 @var{gpgme_key_t} object.  The first one (with index 0) is the primary
 user ID.  The user ID is representable as a number.
 
 @item GPGME_ATTR_NAME
 This is the name belonging to a user ID.  It is representable as a string.
 
 @item GPGME_ATTR_EMAIL
 This is the email address belonging to a user ID.  It is representable
 as a string.
 
 @item GPGME_ATTR_COMMENT
 This is the comment belonging to a user ID.  It is representable as a
 string.
 
 @item GPGME_ATTR_VALIDITY
 This is the validity belonging to a user ID.  It is representable as a
 string and as a number.  See below for a list of available validities.
 
 @item GPGME_ATTR_UID_REVOKED
 This specifies if a user ID is revoked.  It is representable as a
 number, and is @code{1} if the user ID is revoked, and @code{0}
 otherwise.
 
 @item GPGME_ATTR_UID_INVALID
 This specifies if a user ID is invalid.  It is representable as a
 number, and is @code{1} if the user ID is invalid, and @code{0}
 otherwise.
 
 @item GPGME_ATTR_TYPE
 This returns information about the type of key.  For the string function
 this will eother be "PGP" or "X.509".  The integer function returns 0
 for PGP and 1 for X.509.
 
 @item GPGME_ATTR_IS_SECRET
 This specifies if the key is a secret key.  It is representable as a
 number, and is @code{1} if the key is revoked, and @code{0} otherwise.
 
 @item GPGME_ATTR_KEY_REVOKED
 This specifies if a sub key is revoked.  It is representable as a
 number, and is @code{1} if the key is revoked, and @code{0} otherwise.
 
 @item GPGME_ATTR_KEY_INVALID
 This specifies if a sub key is invalid.  It is representable as a
 number, and is @code{1} if the key is invalid, and @code{0} otherwise.
 
 @item GPGME_ATTR_KEY_EXPIRED
 This specifies if a sub key is expired.  It is representable as a
 number, and is @code{1} if the key is expired, and @code{0} otherwise.
 
 @item GPGME_ATTR_KEY_DISABLED
 This specifies if a sub key is disabled.  It is representable as a
 number, and is @code{1} if the key is disabled, and @code{0} otherwise.
 
 @item GPGME_ATTR_KEY_CAPS
 This is a description of the capabilities of a sub key.  It is
 representable as a string.  The string contains the letter ``e'' if
 the key can be used for encryption, ``s'' if the key can be used for
 signatures, and ``c'' if the key can be used for certifications.
 
 @item GPGME_ATTR_CAN_ENCRYPT
 This specifies if a sub key can be used for encryption.  It is
 representable as a number, and is @code{1} if the sub key can be used
 for encryption, and @code{0} otherwise.
 
 @item GPGME_ATTR_CAN_SIGN
 This specifies if a sub key can be used to create data signatures.  It
 is representable as a number, and is @code{1} if the sub key can be
 used for signatures, and @code{0} otherwise.
 
 @item GPGME_ATTR_CAN_CERTIFY
 This specifies if a sub key can be used to create key certificates.
 It is representable as a number, and is @code{1} if the sub key can be
 used for certifications, and @code{0} otherwise.
 
 @item GPGME_ATTR_SERIAL
 The X.509 issuer serial attribute of the key.  It is representable as
 a string.
 
 @item GPGME_ATTR_ISSUE
 The X.509 issuer name attribute of the key.  It is representable as a
 string.
 
 @item GPGME_ATTR_CHAINID
 The X.509 chain ID can be used to build the certification chain.  It
 is representable as a string.
 @end table
 @end deftp
 
 @deftypefun {const char *} gpgme_key_get_string_attr (@w{gpgme_key_t @var{key}}, @w{gpgme_attr_t @var{what}}, @w{const void *@var{reserved}}, @w{int @var{idx}})
 The function @code{gpgme_key_get_string_attr} returns the value of the
 string-representable attribute @var{what} of key @var{key}.  If the
 attribute is an attribute of a sub key or an user ID, @var{idx}
 specifies the sub key or user ID of which the attribute value is
 returned.  The argument @var{reserved} is reserved for later use and
 should be @code{NULL}.
 
 The string returned is only valid as long as the key is valid.
 
 The function returns @code{0} if an attribute can't be returned as a
 string, @var{key} is not a valid pointer, @var{idx} out of range,
 or @var{reserved} not @code{NULL}.
 @end deftypefun
 
 @deftypefun {unsigned long} gpgme_key_get_ulong_attr (@w{gpgme_key_t @var{key}}, @w{gpgme_attr_t @var{what}}, @w{const void *@var{reserved}}, @w{int @var{idx}})
 The function @code{gpgme_key_get_ulong_attr} returns the value of the
 number-representable attribute @var{what} of key @var{key}.  If the
 attribute is an attribute of a sub key or an user ID, @var{idx}
 specifies the sub key or user ID of which the attribute value is
 returned.  The argument @var{reserved} is reserved for later use and
 should be @code{NULL}.
 
 The function returns @code{0} if the attribute can't be returned as a
 number, @var{key} is not a valid pointer, @var{idx} out of range, or
 @var{reserved} not @code{NULL}.
 @end deftypefun
 
 
 @c
 @c Key Signatures
 @c
 The signatures on a key are only available if the key was retrieved
 via a listing operation with the @code{GPGME_KEYLIST_MODE_SIGS} mode
 enabled, because it is expensive to retrieve all signatures of a key.
 
 So, before using the below interfaces to retrieve the signatures on a
 key, you have to make sure that the key was listed with signatures
 enabled.  One convenient, but blocking, way to do this is to use the
 function @code{gpgme_get_key}.
 
 @deftp {Data type} gpgme_attr_t
 The @code{gpgme_attr_t} type is used to specify a key signature
 attribute.  The following attributes are defined:
 
 @table @code
 @item GPGME_ATTR_KEYID
 This is the key ID of the key which was used for the signature.  It is
 representable as a string.
 
 @item GPGME_ATTR_ALGO
 This is the crypto algorithm used to create the signature.  It is
 representable as a string and as a number.  The numbers correspond to
 the @code{enum gcry_pk_algos} values in the gcrypt library.
 
 @item GPGME_ATTR_CREATED
 This is the timestamp at creation time of the signature.  It is
 representable as a number.
 
 @item GPGME_ATTR_EXPIRE
 This is the expiration time of the signature.  It is representable as
 a number.
 
 @item GPGME_ATTR_USERID
 This is the user ID associated with the signing key.  The user ID is
 representable as a number.
 
 @item GPGME_ATTR_NAME
 This is the name belonging to a user ID.  It is representable as a string.
 
 @item GPGME_ATTR_EMAIL
 This is the email address belonging to a user ID.  It is representable
 as a string.
 
 @item GPGME_ATTR_COMMENT
 This is the comment belonging to a user ID.  It is representable as a
 string.
 
 @item GPGME_ATTR_KEY_REVOKED
 This specifies if a key signature is a revocation signature.  It is
 representable as a number, and is @code{1} if the key is revoked, and
 @code{0} otherwise.
 
 @c @item GPGME_ATTR_KEY_EXPIRED
 @c This specifies if a key signature is expired.  It is representable as
 @c a number, and is @code{1} if the key is revoked, and @code{0}
 @c otherwise.
 @c
 @item GPGME_ATTR_SIG_CLASS
 This specifies the signature class of a key signature.  It is
 representable as a number.  The meaning is specific to the crypto
 engine.
 
 @item GPGME_ATTR_SIG_CLASS
 This specifies the signature class of a key signature.  It is
 representable as a number.  The meaning is specific to the crypto
 engine.
 
 @item GPGME_ATTR_SIG_STATUS
 This is the same value as returned by @code{gpgme_get_sig_status}.
 @end table
 @end deftp
 
 @deftypefun {const char *} gpgme_key_sig_get_string_attr (@w{gpgme_key_t @var{key}}, @w{int @var{uid_idx}}, @w{gpgme_attr_t @var{what}}, @w{const void *@var{reserved}}, @w{int @var{idx}})
 The function @code{gpgme_key_sig_get_string_attr} returns the value of
 the string-representable attribute @var{what} of the signature
 @var{idx} on the user ID @var{uid_idx} in the key @var{key}.  The
 argument @var{reserved} is reserved for later use and should be
 @code{NULL}.
 
 The string returned is only valid as long as the key is valid.
 
 The function returns @code{0} if an attribute can't be returned as a
 string, @var{key} is not a valid pointer, @var{uid_idx} or @var{idx}
 out of range, or @var{reserved} not @code{NULL}.
 @end deftypefun
 
 @deftypefun {unsigned long} gpgme_key_sig_get_ulong_attr (@w{gpgme_key_t @var{key}}, @w{int @var{uid_idx}}, @w{gpgme_attr_t @var{what}}, @w{const void *@var{reserved}}, @w{int @var{idx}})
 The function @code{gpgme_key_sig_get_ulong_attr} returns the value of
 the number-representable attribute @var{what} of the signature
 @var{idx} on the user ID @var{uid_idx} in the key @var{key}.  The
 argument @var{reserved} is reserved for later use and should be
 @code{NULL}.
 
 The function returns @code{0} if an attribute can't be returned as a
 string, @var{key} is not a valid pointer, @var{uid_idx} or @var{idx}
 out of range, or @var{reserved} not @code{NULL}.
 @end deftypefun
 
 
 @deftp {Data type} {enum gpgme_sig_stat_t}
 @tindex gpgme_sig_stat_t
 The @code{gpgme_sig_stat_t} type holds the result of a signature check, or
 the combined result of all signatures.  The following results are
 possible:
 
 @table @code
 @item GPGME_SIG_STAT_NONE
 This status should not occur in normal operation.
 
 @item GPGME_SIG_STAT_GOOD
 This status indicates that the signature is valid.  For the combined
 result this status means that all signatures are valid.
 
 @item GPGME_SIG_STAT_GOOD_EXP
 This status indicates that the signature is valid but expired.  For
 the combined result this status means that all signatures are valid
 and expired.
 
 @item GPGME_SIG_STAT_GOOD_EXPKEY
 This status indicates that the signature is valid but the key used to
 verify the signature has expired.  For the combined result this status
 means that all signatures are valid and all keys are expired.
 
 @item GPGME_SIG_STAT_BAD
 This status indicates that the signature is invalid.  For the combined
 result this status means that all signatures are invalid.
 
 @item GPGME_SIG_STAT_NOKEY
 This status indicates that the signature could not be verified due to
 a missing key.  For the combined result this status means that all
 signatures could not be checked due to missing keys.
 
 @item GPGME_SIG_STAT_NOSIG
 This status indicates that the signature data provided was not a real
 signature.
 
 @item GPGME_SIG_STAT_ERROR
 This status indicates that there was some other error which prevented
 the signature verification.
 
 @item GPGME_SIG_STAT_DIFF
 For the combined result this status means that at least two signatures
 have a different status.  You can get each key's status with
 @code{gpgme_get_sig_status}.
 @end table
 @end deftp
 
 @deftypefun {const char *} gpgme_get_sig_status (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{idx}}, @w{gpgme_sig_stat_t *@var{r_stat}}, @w{time_t *@var{r_created}})
 The function @code{gpgme_get_sig_status} is equivalent to:
 
 @example
   gpgme_verify_result_t result;
   gpgme_signature_t sig;
 
   result = gpgme_op_verify_result (ctx);
   sig = result->signatures;
 
   while (sig && idx)
     @{
       sig = sig->next;
       idx--;
     @}
   if (!sig || idx)
     return NULL;
 
   if (r_stat)
     @{
       switch (gpg_err_code (sig->status))
 	@{
 	case GPG_ERR_NO_ERROR:
 	  *r_stat = GPGME_SIG_STAT_GOOD;
 	  break;
 
 	case GPG_ERR_BAD_SIGNATURE:
 	  *r_stat = GPGME_SIG_STAT_BAD;
 	  break;
 
 	case GPG_ERR_NO_PUBKEY:
 	  *r_stat = GPGME_SIG_STAT_NOKEY;
 	  break;
 
 	case GPG_ERR_NO_DATA:
 	  *r_stat = GPGME_SIG_STAT_NOSIG;
 	  break;
 
 	case GPG_ERR_SIG_EXPIRED:
 	  *r_stat = GPGME_SIG_STAT_GOOD_EXP;
 	  break;
 
 	case GPG_ERR_KEY_EXPIRED:
 	  *r_stat = GPGME_SIG_STAT_GOOD_EXPKEY;
 	  break;
 
 	default:
 	  *r_stat = GPGME_SIG_STAT_ERROR;
 	  break;
 	@}
     @}
   if (r_created)
     *r_created = sig->timestamp;
   return sig->fpr;
 @end example
 @end deftypefun
 
 @deftypefun {const char *} gpgme_get_sig_string_attr (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{idx}}, @w{gpgme_attr_t @var{what}}, @w{int @var{whatidx}})
 The function @code{gpgme_get_sig_string_attr} is equivalent to:
 
 @example
   gpgme_verify_result_t result;
   gpgme_signature_t sig;
 
   result = gpgme_op_verify_result (ctx);
   sig = result->signatures;
 
   while (sig && idx)
     @{
       sig = sig->next;
       idx--;
     @}
   if (!sig || idx)
     return NULL;
 
   switch (what)
     @{
     case GPGME_ATTR_FPR:
       return sig->fpr;
 
     case GPGME_ATTR_ERRTOK:
       if (whatidx == 1)
         return sig->wrong_key_usage ? "Wrong_Key_Usage" : "";
       else
 	return "";
     default:
       break;
     @}
 
   return NULL;
 @end example
 @end deftypefun
 
 @deftypefun {const char *} gpgme_get_sig_ulong_attr (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{idx}}, @w{gpgme_attr_t @var{what}}, @w{int @var{whatidx}})
 The function @code{gpgme_get_sig_ulong_attr} is equivalent to:
 
 @example
   gpgme_verify_result_t result;
   gpgme_signature_t sig;
 
   result = gpgme_op_verify_result (ctx);
   sig = result->signatures;
 
   while (sig && idx)
     @{
       sig = sig->next;
       idx--;
     @}
   if (!sig || idx)
     return 0;
 
   switch (what)
     @{
     case GPGME_ATTR_CREATED:
       return sig->timestamp;
 
     case GPGME_ATTR_EXPIRE:
       return sig->exp_timestamp;
 
     case GPGME_ATTR_VALIDITY:
       return (unsigned long) sig->validity;
 
     case GPGME_ATTR_SIG_STATUS:
       switch (sig->status)
 	@{
 	case GPG_ERR_NO_ERROR:
 	  return GPGME_SIG_STAT_GOOD;
 
 	case GPG_ERR_BAD_SIGNATURE:
 	  return GPGME_SIG_STAT_BAD;
 
 	case GPG_ERR_NO_PUBKEY:
 	  return GPGME_SIG_STAT_NOKEY;
 
 	case GPG_ERR_NO_DATA:
 	  return GPGME_SIG_STAT_NOSIG;
 
 	case GPG_ERR_SIG_EXPIRED:
 	  return GPGME_SIG_STAT_GOOD_EXP;
 
 	case GPG_ERR_KEY_EXPIRED:
 	  return GPGME_SIG_STAT_GOOD_EXPKEY;
 
 	default:
 	  return GPGME_SIG_STAT_ERROR;
 	@}
 
     case GPGME_ATTR_SIG_SUMMARY:
       return sig->summary;
 
     default:
       break;
     @}
   return 0;
 @end example
 @end deftypefun
 
 @deftypefun {const char *} gpgme_get_sig_key (@w{gpgme_ctx_t @var{ctx}}, @w{int @var{idx}}, @w{gpgme_key_t *@var{r_key}})
 The function @code{gpgme_get_sig_key} is equivalent to:
 
 @example
   gpgme_verify_result_t result;
   gpgme_signature_t sig;
 
   result = gpgme_op_verify_result (ctx);
   sig = result->signatures;
 
   while (sig && idx)
     @{
       sig = sig->next;
       idx--;
     @}
   if (!sig || idx)
     return gpg_error (GPG_ERR_EOF);
 
   return gpgme_get_key (ctx, sig->fpr, r_key, 0);
 @end example
 @end deftypefun
 
 
 
 
 
 @include lesser.texi
 
 @include gpl.texi
 
 @node Concept Index
 @unnumbered Concept Index
 
 @printindex cp
 
 @node Function and Data Index
 @unnumbered Function and Data Index
 
 @printindex fn
 
 
 @bye
diff --git a/src/gpgme.h.in b/src/gpgme.h.in
index 0a90c8d2..6471f0ad 100644
--- a/src/gpgme.h.in
+++ b/src/gpgme.h.in
@@ -1,2829 +1,2838 @@
 /* gpgme.h - Public interface to GnuPG Made Easy.                   -*- c -*-
  * Copyright (C) 2000 Werner Koch (dd9jn)
  * Copyright (C) 2001-2018 g10 Code GmbH
  *
  * This file is part of GPGME.
  *
  * GPGME is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * GPGME is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, see <https://gnu.org/licenses/>.
  * SPDX-License-Identifier: LGPL-2.1-or-later
  *
  * Generated from gpgme.h.in for @GPGME_CONFIG_HOST@.
  */
 
 #ifndef GPGME_H
 #define GPGME_H
 
 /* Include stdio.h for the FILE type definition.  */
 #include <stdio.h>
 #include <time.h>
 #include <gpg-error.h>
 
 #ifdef __cplusplus
 extern "C" {
 #if 0 /*(Make Emacsen's auto-indent happy.)*/
 }
 #endif
 #endif /* __cplusplus */
 
 
 /* The version of this header should match the one of the library.  Do
  * not use this symbol in your application, use gpgme_check_version
  * instead.  The purpose of this macro is to let autoconf (using the
  * AM_PATH_GPGME macro) check that this header matches the installed
  * library.  */
 #define GPGME_VERSION "@PACKAGE_VERSION@"
 
 /* The version number of this header.  It may be used to handle minor
  * API incompatibilities.  */
 #define GPGME_VERSION_NUMBER @VERSION_NUMBER@
 
 
 /* System specific typedefs.  */
 @INSERT__TYPEDEFS_FOR_GPGME_H@
 
 
 
 /*
  * Check for compiler features.
  */
 #ifdef GPGRT_INLINE
 # define _GPGME_INLINE GPGRT_INLINE
 #elif defined(__GNUC__)
 # define _GPGME_INLINE __inline__
 #elif defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
 # define _GPGME_INLINE inline
 #else
 # define _GPGME_INLINE
 #endif
 
 
 /* The deprecated macro takes the version number of GPGME which
  * introduced the deprecation as parameter for documentation.  */
 #ifdef GPGRT_ATTR_DEPRECATED
 # define _GPGME_DEPRECATED(a,b) GPGRT_ATTR_DEPRECATED
 #elif defined(__GNUC__)
 # define _GPGME_GCC_VERSION (__GNUC__ * 10000 \
                              + __GNUC_MINOR__ * 100 \
                              + __GNUC_PATCHLEVEL__)
 
 # if _GPGME_GCC_VERSION > 30100
 #  define _GPGME_DEPRECATED(a,b)  __attribute__ ((__deprecated__))
 # else
 #  define _GPGME_DEPRECATED(a,b)
 # endif
 #else
 # define _GPGME_DEPRECATED(a,b)
 #endif
 
 
 /* The macro _GPGME_DEPRECATED_OUTSIDE_GPGME suppresses warnings for
  * fields we must access in GPGME for ABI compatibility.  */
 #ifdef _GPGME_IN_GPGME
 #define _GPGME_DEPRECATED_OUTSIDE_GPGME(a,b)
 #else
 #define _GPGME_DEPRECATED_OUTSIDE_GPGME(a,b) _GPGME_DEPRECATED(a,b)
 #endif
 
 /* We used to use some symbols which clash with keywords in some
  * languages.  This macro is used to obsolete them.  */
 #if defined(__cplusplus) || defined(SWIGPYTHON)
 # define _GPGME_OBSOLETE_SOME_SYMBOLS 1
 #endif
 
 
 /* Check for a matching _FILE_OFFSET_BITS definition.  */
 #if @NEED__FILE_OFFSET_BITS@
 #ifndef _FILE_OFFSET_BITS
 #error GPGME was compiled with _FILE_OFFSET_BITS = @NEED__FILE_OFFSET_BITS@, please see the section "Largefile support (LFS)" in the GPGME manual.
 #else
 #if (_FILE_OFFSET_BITS) != (@NEED__FILE_OFFSET_BITS@)
 #error GPGME was compiled with a different value for _FILE_OFFSET_BITS, namely @NEED__FILE_OFFSET_BITS@, please see the section "Largefile support (LFS)" in the GPGME manual.
 #endif
 #endif
 #endif
 
 
 
 /*
  * Some opaque data types used by GPGME.
  */
 
 /* The context holds some global state and configuration options, as
  * well as the results of a crypto operation.  */
 struct gpgme_context;
 typedef struct gpgme_context *gpgme_ctx_t;
 
 /* The data object is used by GPGME to exchange arbitrary data.  */
 struct gpgme_data;
 typedef struct gpgme_data *gpgme_data_t;
 
 
 
 /*
  * Wrappers for the libgpg-error library.  They are generally not
  * needed and the gpg-error versions may be used instead.
  */
 
 typedef gpg_error_t gpgme_error_t;
 typedef gpg_err_code_t gpgme_err_code_t;
 typedef gpg_err_source_t gpgme_err_source_t;
 
 
 static _GPGME_INLINE gpgme_error_t
 gpgme_err_make (gpgme_err_source_t source, gpgme_err_code_t code)
 {
   return gpg_err_make (source, code);
 }
 
 
 /* The user can define GPGME_ERR_SOURCE_DEFAULT before including this
  * file to specify a default source for gpgme_error.  */
 #ifndef GPGME_ERR_SOURCE_DEFAULT
 #define GPGME_ERR_SOURCE_DEFAULT  GPG_ERR_SOURCE_USER_1
 #endif
 
 static _GPGME_INLINE gpgme_error_t
 gpgme_error (gpgme_err_code_t code)
 {
   return gpgme_err_make (GPGME_ERR_SOURCE_DEFAULT, code);
 }
 
 
 static _GPGME_INLINE gpgme_err_code_t
 gpgme_err_code (gpgme_error_t err)
 {
   return gpg_err_code (err);
 }
 
 
 static _GPGME_INLINE gpgme_err_source_t
 gpgme_err_source (gpgme_error_t err)
 {
   return gpg_err_source (err);
 }
 
 
 /* Return a pointer to a string containing a description of the error
  * code in the error value ERR.  This function is not thread safe.  */
 const char *gpgme_strerror (gpgme_error_t err);
 
 /* Return the error string for ERR in the user-supplied buffer BUF of
  * size BUFLEN.  This function is, in contrast to gpg_strerror,
  * thread-safe if a thread-safe strerror_r() function is provided by
  * the system.  If the function succeeds, 0 is returned and BUF
  * contains the string describing the error.  If the buffer was not
  * large enough, ERANGE is returned and BUF contains as much of the
  * beginning of the error string as fits into the buffer.  */
 int gpgme_strerror_r (gpg_error_t err, char *buf, size_t buflen);
 
 /* Return a pointer to a string containing a description of the error
  * source in the error value ERR.  */
 const char *gpgme_strsource (gpgme_error_t err);
 
 /* Retrieve the error code for the system error ERR.  This returns
  * GPG_ERR_UNKNOWN_ERRNO if the system error is not mapped (report
  * this).  */
 gpgme_err_code_t gpgme_err_code_from_errno (int err);
 
 /* Retrieve the system error for the error code CODE.  This returns 0
  * if CODE is not a system error code.  */
 int gpgme_err_code_to_errno (gpgme_err_code_t code);
 
 /* Retrieve the error code directly from the ERRNO variable.  This
  * returns GPG_ERR_UNKNOWN_ERRNO if the system error is not mapped
  * (report this) and GPG_ERR_MISSING_ERRNO if ERRNO has the value 0. */
 gpgme_err_code_t gpgme_err_code_from_syserror (void);
 
 /* Set the ERRNO variable.  This function is the preferred way to set
  * ERRNO due to peculiarities on WindowsCE.  */
 void gpgme_err_set_errno (int err);
 
 /* Return an error value with the error source SOURCE and the system
  *  error ERR.  FIXME: Should be inline.  */
 gpgme_error_t gpgme_err_make_from_errno (gpgme_err_source_t source, int err);
 
 /* Return an error value with the system error ERR.
  * inline.  */
 gpgme_error_t gpgme_error_from_errno (int err);
 
 
 static _GPGME_INLINE gpgme_error_t
 gpgme_error_from_syserror (void)
 {
   return gpgme_error (gpgme_err_code_from_syserror ());
 }
 
 
 
 /*
  * Various constants and types
  */
 
 /* The possible encoding mode of gpgme_data_t objects.  */
 typedef enum
   {
     GPGME_DATA_ENCODING_NONE   = 0,	/* Not specified.  */
     GPGME_DATA_ENCODING_BINARY = 1,
     GPGME_DATA_ENCODING_BASE64 = 2,
     GPGME_DATA_ENCODING_ARMOR  = 3,	/* Either PEM or OpenPGP Armor.  */
     GPGME_DATA_ENCODING_URL    = 4,     /* LF delimited URL list.        */
     GPGME_DATA_ENCODING_URLESC = 5,     /* Ditto, but percent escaped.   */
     GPGME_DATA_ENCODING_URL0   = 6,     /* Nul delimited URL list.       */
     GPGME_DATA_ENCODING_MIME   = 7      /* Data is a MIME part.          */
   }
 gpgme_data_encoding_t;
 
 
 /* Known data types.  */
 typedef enum
   {
     GPGME_DATA_TYPE_INVALID      = 0,   /* Not detected.  */
     GPGME_DATA_TYPE_UNKNOWN      = 1,
     GPGME_DATA_TYPE_PGP_SIGNED   = 0x10,
     GPGME_DATA_TYPE_PGP_ENCRYPTED= 0x11,
     GPGME_DATA_TYPE_PGP_OTHER    = 0x12,
     GPGME_DATA_TYPE_PGP_KEY      = 0x13,
     GPGME_DATA_TYPE_PGP_SIGNATURE= 0x18, /* Detached signature */
     GPGME_DATA_TYPE_CMS_SIGNED   = 0x20,
     GPGME_DATA_TYPE_CMS_ENCRYPTED= 0x21,
     GPGME_DATA_TYPE_CMS_OTHER    = 0x22,
     GPGME_DATA_TYPE_X509_CERT    = 0x23,
     GPGME_DATA_TYPE_PKCS12       = 0x24,
   }
 gpgme_data_type_t;
 
 
 /* Public key algorithms.  */
 typedef enum
   {
     GPGME_PK_RSA   = 1,
     GPGME_PK_RSA_E = 2,
     GPGME_PK_RSA_S = 3,
     GPGME_PK_ELG_E = 16,
     GPGME_PK_DSA   = 17,
     GPGME_PK_ECC   = 18,
     GPGME_PK_ELG   = 20,
     GPGME_PK_ECDSA = 301,
     GPGME_PK_ECDH  = 302,
     GPGME_PK_EDDSA = 303
   }
 gpgme_pubkey_algo_t;
 
 
 /* Hash algorithms (the values match those from libgcrypt).  */
 typedef enum
   {
     GPGME_MD_NONE          = 0,
     GPGME_MD_MD5           = 1,
     GPGME_MD_SHA1          = 2,
     GPGME_MD_RMD160        = 3,
     GPGME_MD_MD2           = 5,
     GPGME_MD_TIGER         = 6,   /* TIGER/192. */
     GPGME_MD_HAVAL         = 7,   /* HAVAL, 5 pass, 160 bit. */
     GPGME_MD_SHA256        = 8,
     GPGME_MD_SHA384        = 9,
     GPGME_MD_SHA512        = 10,
     GPGME_MD_SHA224        = 11,
     GPGME_MD_MD4           = 301,
     GPGME_MD_CRC32	   = 302,
     GPGME_MD_CRC32_RFC1510 = 303,
     GPGME_MD_CRC24_RFC2440 = 304
   }
 gpgme_hash_algo_t;
 
 
 /* The available signature modes.  */
 typedef enum
   {
     GPGME_SIG_MODE_NORMAL = 0,
     GPGME_SIG_MODE_DETACH = 1,
     GPGME_SIG_MODE_CLEAR  = 2
   }
 gpgme_sig_mode_t;
 
 
 /* The available validities for a key.  */
 typedef enum
   {
     GPGME_VALIDITY_UNKNOWN   = 0,
     GPGME_VALIDITY_UNDEFINED = 1,
     GPGME_VALIDITY_NEVER     = 2,
     GPGME_VALIDITY_MARGINAL  = 3,
     GPGME_VALIDITY_FULL      = 4,
     GPGME_VALIDITY_ULTIMATE  = 5
   }
 gpgme_validity_t;
 
 
 /* The TOFU policies. */
 typedef enum
   {
     GPGME_TOFU_POLICY_NONE    = 0,
     GPGME_TOFU_POLICY_AUTO    = 1,
     GPGME_TOFU_POLICY_GOOD    = 2,
     GPGME_TOFU_POLICY_UNKNOWN = 3,
     GPGME_TOFU_POLICY_BAD     = 4,
     GPGME_TOFU_POLICY_ASK     = 5
   }
 gpgme_tofu_policy_t;
 
 
 /* The key origin values. */
 typedef enum
   {
     GPGME_KEYORG_UNKNOWN      = 0,
     GPGME_KEYORG_KS           = 1,
     GPGME_KEYORG_DANE         = 3,
     GPGME_KEYORG_WKD          = 4,
     GPGME_KEYORG_URL          = 5,
     GPGME_KEYORG_FILE         = 6,
     GPGME_KEYORG_SELF         = 7,
     GPGME_KEYORG_OTHER        = 31
   }
 gpgme_keyorg_t;
 
 
 /* The available protocols.  */
 typedef enum
   {
     GPGME_PROTOCOL_OpenPGP = 0,  /* The default mode.  */
     GPGME_PROTOCOL_CMS     = 1,
     GPGME_PROTOCOL_GPGCONF = 2,  /* Special code for gpgconf.  */
     GPGME_PROTOCOL_ASSUAN  = 3,  /* Low-level access to an Assuan server.  */
     GPGME_PROTOCOL_G13     = 4,
     GPGME_PROTOCOL_UISERVER= 5,
     GPGME_PROTOCOL_SPAWN   = 6,  /* Direct access to any program.  */
     GPGME_PROTOCOL_DEFAULT = 254,
     GPGME_PROTOCOL_UNKNOWN = 255
   }
 gpgme_protocol_t;
 /* Convenience macro for the surprisingly mixed spelling.  */
 #define GPGME_PROTOCOL_OPENPGP GPGME_PROTOCOL_OpenPGP
 
 
 /* The available keylist mode flags.  */
 #define GPGME_KEYLIST_MODE_LOCAL		1
 #define GPGME_KEYLIST_MODE_EXTERN		2
 #define GPGME_KEYLIST_MODE_SIGS			4
 #define GPGME_KEYLIST_MODE_SIG_NOTATIONS	8
 #define GPGME_KEYLIST_MODE_WITH_SECRET       	16
 #define GPGME_KEYLIST_MODE_WITH_TOFU       	32
 #define GPGME_KEYLIST_MODE_WITH_KEYGRIP       	64
 #define GPGME_KEYLIST_MODE_EPHEMERAL            128
 #define GPGME_KEYLIST_MODE_VALIDATE		256
 
 #define GPGME_KEYLIST_MODE_LOCATE		(1|2)
 
 typedef unsigned int gpgme_keylist_mode_t;
 
 
 /* The pinentry modes. */
 typedef enum
   {
     GPGME_PINENTRY_MODE_DEFAULT  = 0,
     GPGME_PINENTRY_MODE_ASK      = 1,
     GPGME_PINENTRY_MODE_CANCEL   = 2,
     GPGME_PINENTRY_MODE_ERROR    = 3,
     GPGME_PINENTRY_MODE_LOOPBACK = 4
   }
 gpgme_pinentry_mode_t;
 
 
 /* The available export mode flags.  */
 #define GPGME_EXPORT_MODE_EXTERN                2
 #define GPGME_EXPORT_MODE_MINIMAL               4
 #define GPGME_EXPORT_MODE_SECRET               16
 #define GPGME_EXPORT_MODE_RAW                  32
 #define GPGME_EXPORT_MODE_PKCS12               64
 #define GPGME_EXPORT_MODE_SSH                 256
 
 typedef unsigned int gpgme_export_mode_t;
 
 
 /* Flags for the audit log functions.  */
 #define GPGME_AUDITLOG_DEFAULT   0
 #define GPGME_AUDITLOG_HTML      1
 #define GPGME_AUDITLOG_DIAG      2
 #define GPGME_AUDITLOG_WITH_HELP 128
 
 
 /* The available signature notation flags.  */
 #define GPGME_SIG_NOTATION_HUMAN_READABLE	1
 #define GPGME_SIG_NOTATION_CRITICAL		2
 
 typedef unsigned int gpgme_sig_notation_flags_t;
 
 /* An object to hold information about notation data.  This structure
  * shall be considered read-only and an application must not allocate
  * such a structure on its own.  */
 struct _gpgme_sig_notation
 {
   struct _gpgme_sig_notation *next;
 
   /* If NAME is a null pointer, then VALUE contains a policy URL
    * rather than a notation.  */
   char *name;
 
   /* The value of the notation data.  */
   char *value;
 
   /* The length of the name of the notation data.  */
   int name_len;
 
   /* The length of the value of the notation data.  */
   int value_len;
 
   /* The accumulated flags.  */
   gpgme_sig_notation_flags_t flags;
 
   /* Notation data is human-readable.  */
   unsigned int human_readable : 1;
 
   /* Notation data is critical.  */
   unsigned int critical : 1;
 
   /* Internal to GPGME, do not use.  */
   int _unused : 30;
 };
 typedef struct _gpgme_sig_notation *gpgme_sig_notation_t;
 
 
 
 /*
  * Public structures.
  */
 
 /* The engine information structure.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_engine_info
 {
   struct _gpgme_engine_info *next;
 
   /* The protocol ID.  */
   gpgme_protocol_t protocol;
 
   /* The file name of the engine binary.  */
   char *file_name;
 
   /* The version string of the installed engine.  */
   char *version;
 
   /* The minimum version required for GPGME.  */
   const char *req_version;
 
   /* The home directory used, or NULL if default.  */
   char *home_dir;
 };
 typedef struct _gpgme_engine_info *gpgme_engine_info_t;
 
 
 /* An object with TOFU information.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_tofu_info
 {
   struct _gpgme_tofu_info *next;
 
   /* The TOFU validity:
    *  0 := conflict
    *  1 := key without history
    *  2 := key with too little history
    *  3 := key with enough history for basic trust
    *  4 := key with a lot of history
    */
   unsigned int validity : 3;
 
   /* The TOFU policy (gpgme_tofu_policy_t).  */
   unsigned int policy : 4;
 
   unsigned int _rfu : 25;
 
   /* Number of signatures seen for this binding.  Capped at USHRT_MAX.  */
   unsigned short signcount;
   /* Number of encryptions done with this binding.  Capped at USHRT_MAX.  */
   unsigned short encrcount;
 
   /* Number of seconds since Epoch when the first and the most
    * recently seen message were verified/decrypted.  0 means unknown. */
   unsigned long signfirst;
   unsigned long signlast;
   unsigned long encrfirst;
   unsigned long encrlast;
 
   /* If non-NULL a human readable string summarizing the TOFU data. */
   char *description;
 };
 typedef struct _gpgme_tofu_info *gpgme_tofu_info_t;
 
 
 /* A subkey from a key.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_subkey
 {
   struct _gpgme_subkey *next;
 
   /* True if subkey is revoked.  */
   unsigned int revoked : 1;
 
   /* True if subkey is expired.  */
   unsigned int expired : 1;
 
   /* True if subkey is disabled.  */
   unsigned int disabled : 1;
 
   /* True if subkey is invalid.  */
   unsigned int invalid : 1;
 
   /* True if subkey can be used for encryption.  */
   unsigned int can_encrypt : 1;
 
   /* True if subkey can be used for signing.  */
   unsigned int can_sign : 1;
 
   /* True if subkey can be used for certification.  */
   unsigned int can_certify : 1;
 
   /* True if subkey is secret.  */
   unsigned int secret : 1;
 
   /* True if subkey can be used for authentication.  */
   unsigned int can_authenticate : 1;
 
   /* True if subkey is qualified for signatures according to German law.  */
   unsigned int is_qualified : 1;
 
   /* True if the secret key is stored on a smart card.  */
   unsigned int is_cardkey : 1;
 
   /* True if the key is compliant to the de-vs mode.  */
   unsigned int is_de_vs : 1;
 
   /* Internal to GPGME, do not use.  */
   unsigned int _unused : 20;
 
   /* Public key algorithm supported by this subkey.  */
   gpgme_pubkey_algo_t pubkey_algo;
 
   /* Length of the subkey.  */
   unsigned int length;
 
   /* The key ID of the subkey.  */
   char *keyid;
 
   /* Internal to GPGME, do not use.  */
   char _keyid[16 + 1];
 
   /* The fingerprint of the subkey in hex digit form.  */
   char *fpr;
 
   /* The creation timestamp, -1 if invalid, 0 if not available.  */
   long int timestamp;
 
   /* The expiration timestamp, 0 if the subkey does not expire.  */
   long int expires;
 
   /* The serial number of a smart card holding this key or NULL.  */
   char *card_number;
 
   /* The name of the curve for ECC algorithms or NULL.  */
   char *curve;
 
   /* The keygrip of the subkey in hex digit form or NULL if not available.  */
   char *keygrip;
 };
 typedef struct _gpgme_subkey *gpgme_subkey_t;
 
 
 /* A signature on a user ID.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_key_sig
 {
   struct _gpgme_key_sig *next;
 
   /* True if the signature is a revocation signature.  */
   unsigned int revoked : 1;
 
   /* True if the signature is expired.  */
   unsigned int expired : 1;
 
   /* True if the signature is invalid.  */
   unsigned int invalid : 1;
 
   /* True if the signature should be exported.  */
   unsigned int exportable : 1;
 
   /* Internal to GPGME, do not use.  */
-  unsigned int _unused : 28;
+  unsigned int _unused : 12;
+
+  /* The depth of a trust signature, 0 if no trust signature.  */
+  unsigned int trust_depth : 8;
+
+  /* The trust value of a trust signature, 0 if no trust signature.  */
+  unsigned int trust_value : 8;
 
   /* The public key algorithm used to create the signature.  */
   gpgme_pubkey_algo_t pubkey_algo;
 
   /* The key ID of key used to create the signature.  */
   char *keyid;
 
   /* Internal to GPGME, do not use.  */
   char _keyid[16 + 1];
 
   /* The creation timestamp, -1 if invalid, 0 if not available.  */
   long int timestamp;
 
   /* The expiration timestamp, 0 if the subkey does not expire.  */
   long int expires;
 
+  /* The scope of a trust signature.  Might be NULL.  */
+  char *trust_scope;
+
   /* Same as in gpgme_signature_t.  */
   gpgme_error_t status;
 
   /* Deprecated; use SIG_CLASS instead.  */
 #ifdef _GPGME_OBSOLETE_SOME_SYMBOLS
   unsigned int _obsolete_class _GPGME_DEPRECATED(0,4);
 #else
   unsigned int class _GPGME_DEPRECATED_OUTSIDE_GPGME(0,4);
 #endif
 
   /* The user ID string.  */
   char *uid;
 
   /* The name part of the user ID.  */
   char *name;
 
   /* The email part of the user ID.  */
   char *email;
 
   /* The comment part of the user ID.  */
   char *comment;
 
   /* Crypto backend specific signature class.  */
   unsigned int sig_class;
 
   /* Notation data and policy URLs.  */
   gpgme_sig_notation_t notations;
 
   /* Internal to GPGME, do not use.  */
   gpgme_sig_notation_t _last_notation;
 };
 typedef struct _gpgme_key_sig *gpgme_key_sig_t;
 
 
 /* An user ID from a key.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_user_id
 {
   struct _gpgme_user_id *next;
 
   /* True if the user ID is revoked.  */
   unsigned int revoked : 1;
 
   /* True if the user ID is invalid.  */
   unsigned int invalid : 1;
 
   /* Internal to GPGME, do not use.  */
   unsigned int _unused : 25;
 
   /* Origin of this user ID.  */
   unsigned int origin : 5;
 
   /* The validity of the user ID.  */
   gpgme_validity_t validity;
 
   /* The user ID string.  */
   char *uid;
 
   /* The name part of the user ID.  */
   char *name;
 
   /* The email part of the user ID.  */
   char *email;
 
   /* The comment part of the user ID.  */
   char *comment;
 
   /* The signatures of the user ID.  */
   gpgme_key_sig_t signatures;
 
   /* Internal to GPGME, do not use.  */
   gpgme_key_sig_t _last_keysig;
 
   /* The mail address (addr-spec from RFC5322) of the UID string.
    * This is general the same as the EMAIL part of this struct but
    * might be slightly different.  If no mail address is available
    * NULL is stored.  */
   char *address;
 
   /* The malloced TOFU information or NULL.  */
   gpgme_tofu_info_t tofu;
 
   /* Time of the last refresh of this user id.  0 if unknown.  */
   unsigned long last_update;
 
   /* The string to exactly identify a userid.  Might be NULL.  */
   char *uidhash;
 };
 typedef struct _gpgme_user_id *gpgme_user_id_t;
 
 
 /* A key from the keyring.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_key
 {
   /* Internal to GPGME, do not use.  */
   unsigned int _refs;
 
   /* True if key is revoked.  */
   unsigned int revoked : 1;
 
   /* True if key is expired.  */
   unsigned int expired : 1;
 
   /* True if key is disabled.  */
   unsigned int disabled : 1;
 
   /* True if key is invalid.  */
   unsigned int invalid : 1;
 
   /* True if key can be used for encryption.  */
   unsigned int can_encrypt : 1;
 
   /* True if key can be used for signing.  */
   unsigned int can_sign : 1;
 
   /* True if key can be used for certification.  */
   unsigned int can_certify : 1;
 
   /* True if key is secret.  */
   unsigned int secret : 1;
 
   /* True if key can be used for authentication.  */
   unsigned int can_authenticate : 1;
 
   /* True if subkey is qualified for signatures according to German law.  */
   unsigned int is_qualified : 1;
 
   /* Internal to GPGME, do not use.  */
   unsigned int _unused : 17;
 
   /* Origin of this key.  */
   unsigned int origin : 5;
 
   /* This is the protocol supported by this key.  */
   gpgme_protocol_t protocol;
 
   /* If protocol is GPGME_PROTOCOL_CMS, this string contains the
      issuer serial.  */
   char *issuer_serial;
 
   /* If protocol is GPGME_PROTOCOL_CMS, this string contains the
      issuer name.  */
   char *issuer_name;
 
   /* If protocol is GPGME_PROTOCOL_CMS, this string contains the chain
      ID.  */
   char *chain_id;
 
   /* If protocol is GPGME_PROTOCOL_OpenPGP, this field contains the
      owner trust.  */
   gpgme_validity_t owner_trust;
 
   /* The subkeys of the key.  */
   gpgme_subkey_t subkeys;
 
   /* The user IDs of the key.  */
   gpgme_user_id_t uids;
 
   /* Internal to GPGME, do not use.  */
   gpgme_subkey_t _last_subkey;
 
   /* Internal to GPGME, do not use.  */
   gpgme_user_id_t _last_uid;
 
   /* The keylist mode that was active when listing the key.  */
   gpgme_keylist_mode_t keylist_mode;
 
   /* This field gives the fingerprint of the primary key.  Note that
    * this is a copy of the FPR of the first subkey.  We need it here
    * to allow for an incomplete key object.  */
   char *fpr;
 
   /* Time of the last refresh of the entire key.  0 if unknown.  */
   unsigned long last_update;
 };
 typedef struct _gpgme_key *gpgme_key_t;
 
 
 /* An invalid key object.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_invalid_key
 {
   struct _gpgme_invalid_key *next;
 
   /* The string used to request the key.  Despite the name this may
    * not be a fingerprint.  */
   char *fpr;
 
   /* The error code.  */
   gpgme_error_t reason;
 };
 typedef struct _gpgme_invalid_key *gpgme_invalid_key_t;
 
 
 
 /*
  * Types for callback functions.
  */
 
 /* Request a passphrase from the user.  */
 typedef gpgme_error_t (*gpgme_passphrase_cb_t) (void *hook,
 						const char *uid_hint,
 						const char *passphrase_info,
 						int prev_was_bad, int fd);
 
 /* Inform the user about progress made.  */
 typedef void (*gpgme_progress_cb_t) (void *opaque, const char *what,
 				     int type, int current, int total);
 
 /* Status messages from gpg. */
 typedef gpgme_error_t (*gpgme_status_cb_t) (void *opaque, const char *keyword,
                                             const char *args);
 
 /* Interact with the user about an edit operation.  */
 typedef gpgme_error_t (*gpgme_interact_cb_t) (void *opaque,
                                               const char *keyword,
                                               const char *args, int fd);
 
 
 
 /*
  * Context management functions.
  */
 
 /* Create a new context and return it in CTX.  */
 gpgme_error_t gpgme_new (gpgme_ctx_t *ctx);
 
 /* Release the context CTX.  */
 void gpgme_release (gpgme_ctx_t ctx);
 
 /* Set the flag NAME for CTX to VALUE.  */
 gpgme_error_t gpgme_set_ctx_flag (gpgme_ctx_t ctx,
                                   const char *name, const char *value);
 
 /* Get the value of the flag NAME from CTX.  */
 const char *gpgme_get_ctx_flag (gpgme_ctx_t ctx, const char *name);
 
 /* Set the protocol to be used by CTX to PROTO.  */
 gpgme_error_t gpgme_set_protocol (gpgme_ctx_t ctx, gpgme_protocol_t proto);
 
 /* Get the protocol used with CTX */
 gpgme_protocol_t gpgme_get_protocol (gpgme_ctx_t ctx);
 
 /* Set the crypto protocol to be used by CTX to PROTO.
  * gpgme_set_protocol actually sets the backend engine.  This sets the
  * crypto protocol used in engines that support more than one crypto
  * prococol (for example, an UISERVER can support OpenPGP and CMS).
  * This is reset to the default with gpgme_set_protocol.  */
 gpgme_error_t gpgme_set_sub_protocol (gpgme_ctx_t ctx,
 				      gpgme_protocol_t proto);
 
 /* Get the sub protocol.  */
 gpgme_protocol_t gpgme_get_sub_protocol (gpgme_ctx_t ctx);
 
 /* Get the string describing protocol PROTO, or NULL if invalid.  */
 const char *gpgme_get_protocol_name (gpgme_protocol_t proto);
 
 /* If YES is non-zero, enable armor mode in CTX, disable it otherwise.  */
 void gpgme_set_armor (gpgme_ctx_t ctx, int yes);
 
 /* Return non-zero if armor mode is set in CTX.  */
 int gpgme_get_armor (gpgme_ctx_t ctx);
 
 /* If YES is non-zero, enable text mode in CTX, disable it otherwise.  */
 void gpgme_set_textmode (gpgme_ctx_t ctx, int yes);
 
 /* Return non-zero if text mode is set in CTX.  */
 int gpgme_get_textmode (gpgme_ctx_t ctx);
 
 /* If YES is non-zero, enable offline mode in CTX, disable it otherwise.  */
 void gpgme_set_offline (gpgme_ctx_t ctx, int yes);
 
 /* Return non-zero if offline mode is set in CTX.  */
 int gpgme_get_offline (gpgme_ctx_t ctx);
 
 /* Use whatever the default of the backend crypto engine is.  */
 #define GPGME_INCLUDE_CERTS_DEFAULT	-256
 
 /* Include up to NR_OF_CERTS certificates in an S/MIME message.  */
 void gpgme_set_include_certs (gpgme_ctx_t ctx, int nr_of_certs);
 
 /* Return the number of certs to include in an S/MIME message.  */
 int gpgme_get_include_certs (gpgme_ctx_t ctx);
 
 /* Set keylist mode in CTX to MODE.  */
 gpgme_error_t gpgme_set_keylist_mode (gpgme_ctx_t ctx,
 				      gpgme_keylist_mode_t mode);
 
 /* Get keylist mode in CTX.  */
 gpgme_keylist_mode_t gpgme_get_keylist_mode (gpgme_ctx_t ctx);
 
 /* Set the pinentry mode for CTX to MODE. */
 gpgme_error_t gpgme_set_pinentry_mode (gpgme_ctx_t ctx,
                                        gpgme_pinentry_mode_t mode);
 
 /* Get the pinentry mode of CTX.  */
 gpgme_pinentry_mode_t gpgme_get_pinentry_mode (gpgme_ctx_t ctx);
 
 /* Set the passphrase callback function in CTX to CB.  HOOK_VALUE is
  * passed as first argument to the passphrase callback function.  */
 void gpgme_set_passphrase_cb (gpgme_ctx_t ctx,
                               gpgme_passphrase_cb_t cb, void *hook_value);
 
 /* Get the current passphrase callback function in *CB and the current
  * hook value in *HOOK_VALUE.  */
 void gpgme_get_passphrase_cb (gpgme_ctx_t ctx, gpgme_passphrase_cb_t *cb,
 			      void **hook_value);
 
 /* Set the progress callback function in CTX to CB.  HOOK_VALUE is
  * passed as first argument to the progress callback function.  */
 void gpgme_set_progress_cb (gpgme_ctx_t c, gpgme_progress_cb_t cb,
 			    void *hook_value);
 
 /* Get the current progress callback function in *CB and the current
  * hook value in *HOOK_VALUE.  */
 void gpgme_get_progress_cb (gpgme_ctx_t ctx, gpgme_progress_cb_t *cb,
 			    void **hook_value);
 
 /* Set the status callback function in CTX to CB.  HOOK_VALUE is
  * passed as first argument to the status callback function.  */
 void gpgme_set_status_cb (gpgme_ctx_t c, gpgme_status_cb_t cb,
                           void *hook_value);
 
 /* Get the current status callback function in *CB and the current
  * hook value in *HOOK_VALUE.  */
 void gpgme_get_status_cb (gpgme_ctx_t ctx, gpgme_status_cb_t *cb,
                           void **hook_value);
 
 /* This function sets the locale for the context CTX, or the default
  * locale if CTX is a null pointer.  */
 gpgme_error_t gpgme_set_locale (gpgme_ctx_t ctx, int category,
 				const char *value);
 
 /* Get the information about the configured engines.  A pointer to the
  * first engine in the statically allocated linked list is returned.
  * The returned data is valid until the next gpgme_ctx_set_engine_info.  */
 gpgme_engine_info_t gpgme_ctx_get_engine_info (gpgme_ctx_t ctx);
 
 /* Set the engine info for the context CTX, protocol PROTO, to the
  * file name FILE_NAME and the home directory HOME_DIR.  */
 gpgme_error_t gpgme_ctx_set_engine_info (gpgme_ctx_t ctx,
 					 gpgme_protocol_t proto,
 					 const char *file_name,
 					 const char *home_dir);
 
 /* Delete all signers from CTX.  */
 void gpgme_signers_clear (gpgme_ctx_t ctx);
 
 /* Add KEY to list of signers in CTX.  */
 gpgme_error_t gpgme_signers_add (gpgme_ctx_t ctx, const gpgme_key_t key);
 
 /* Return the number of signers in CTX.  */
 unsigned int gpgme_signers_count (const gpgme_ctx_t ctx);
 
 /* Return the SEQth signer's key in CTX.  */
 gpgme_key_t gpgme_signers_enum (const gpgme_ctx_t ctx, int seq);
 
 /* Clear all notation data from the context.  */
 void gpgme_sig_notation_clear (gpgme_ctx_t ctx);
 
 /* Add the human-readable notation data with name NAME and value VALUE
  * to the context CTX, using the flags FLAGS.  If NAME is NULL, then
  * VALUE should be a policy URL.  The flag
  * GPGME_SIG_NOTATION_HUMAN_READABLE is forced to be true for notation
  * data, and false for policy URLs.  */
 gpgme_error_t gpgme_sig_notation_add (gpgme_ctx_t ctx, const char *name,
 				      const char *value,
 				      gpgme_sig_notation_flags_t flags);
 
 /* Get the sig notations for this context.  */
 gpgme_sig_notation_t gpgme_sig_notation_get (gpgme_ctx_t ctx);
 
 /* Store a sender address in the context.  */
 gpgme_error_t gpgme_set_sender (gpgme_ctx_t ctx, const char *address);
 
 /* Get the sender address from the context.  */
 const char *gpgme_get_sender (gpgme_ctx_t ctx);
 
 
 
 /*
  * Run control.
  */
 
 /* The type of an I/O callback function.  */
 typedef gpgme_error_t (*gpgme_io_cb_t) (void *data, int fd);
 
 /* The type of a function that can register FNC as the I/O callback
  * function for the file descriptor FD with direction dir (0: for writing,
  * 1: for reading).  FNC_DATA should be passed as DATA to FNC.  The
  * function should return a TAG suitable for the corresponding
  * gpgme_remove_io_cb_t, and an error value.  */
 typedef gpgme_error_t (*gpgme_register_io_cb_t) (void *data, int fd, int dir,
 						 gpgme_io_cb_t fnc,
 						 void *fnc_data, void **tag);
 
 /* The type of a function that can remove a previously registered I/O
  * callback function given TAG as returned by the register
  * function.  */
 typedef void (*gpgme_remove_io_cb_t) (void *tag);
 
 typedef enum
   {
     GPGME_EVENT_START,
     GPGME_EVENT_DONE,
     GPGME_EVENT_NEXT_KEY,
     GPGME_EVENT_NEXT_TRUSTITEM  /* NOT USED.  */
   }
 gpgme_event_io_t;
 
 struct gpgme_io_event_done_data
 {
   /* A fatal IPC error or an operational error in state-less
    * protocols.  */
   gpgme_error_t err;
 
   /* An operational errors in session-based protocols.  */
   gpgme_error_t op_err;
 };
 typedef struct gpgme_io_event_done_data *gpgme_io_event_done_data_t;
 
 /* The type of a function that is called when a context finished an
  * operation.  */
 typedef void (*gpgme_event_io_cb_t) (void *data, gpgme_event_io_t type,
 				     void *type_data);
 
 struct gpgme_io_cbs
 {
   gpgme_register_io_cb_t add;
   void *add_priv;
   gpgme_remove_io_cb_t remove;
   gpgme_event_io_cb_t event;
   void *event_priv;
 };
 typedef struct gpgme_io_cbs *gpgme_io_cbs_t;
 
 /* Set the I/O callback functions in CTX to IO_CBS.  */
 void gpgme_set_io_cbs (gpgme_ctx_t ctx, gpgme_io_cbs_t io_cbs);
 
 /* Get the current I/O callback functions.  */
 void gpgme_get_io_cbs (gpgme_ctx_t ctx, gpgme_io_cbs_t io_cbs);
 
 /* Wrappers around the internal I/O functions for use with
  * gpgme_passphrase_cb_t and gpgme_interact_cb_t.  */
 @API__SSIZE_T@ gpgme_io_read (int fd, void *buffer, size_t count);
 @API__SSIZE_T@ gpgme_io_write (int fd, const void *buffer, size_t count);
 int     gpgme_io_writen (int fd, const void *buffer, size_t count);
 
 /* Process the pending operation and, if HANG is non-zero, wait for
  * the pending operation to finish.  */
 gpgme_ctx_t gpgme_wait (gpgme_ctx_t ctx, gpgme_error_t *status, int hang);
 
 gpgme_ctx_t gpgme_wait_ext (gpgme_ctx_t ctx, gpgme_error_t *status,
 			    gpgme_error_t *op_err, int hang);
 
 /* Cancel a pending asynchronous operation.  */
 gpgme_error_t gpgme_cancel (gpgme_ctx_t ctx);
 
 /* Cancel a pending operation asynchronously.  */
 gpgme_error_t gpgme_cancel_async (gpgme_ctx_t ctx);
 
 
 
 /*
  * Functions to handle data objects.
  */
 
 /* Read up to SIZE bytes into buffer BUFFER from the data object with
  * the handle HANDLE.  Return the number of characters read, 0 on EOF
  * and -1 on error.  If an error occurs, errno is set.  */
 typedef @API__SSIZE_T@ (*gpgme_data_read_cb_t) (void *handle, void *buffer,
 					 size_t size);
 
 /* Write up to SIZE bytes from buffer BUFFER to the data object with
  * the handle HANDLE.  Return the number of characters written, or -1
  * on error.  If an error occurs, errno is set.  */
 typedef @API__SSIZE_T@ (*gpgme_data_write_cb_t) (void *handle, const void *buffer,
 					  size_t size);
 
 /* Set the current position from where the next read or write starts
  * in the data object with the handle HANDLE to OFFSET, relativ to
  * WHENCE.  Returns the new offset in bytes from the beginning of the
  * data object.  */
 typedef @API__OFF_T@ (*gpgme_data_seek_cb_t) (void *handle,
                                        @API__OFF_T@ offset, int whence);
 
 /* Close the data object with the handle HANDLE.  */
 typedef void (*gpgme_data_release_cb_t) (void *handle);
 
 struct gpgme_data_cbs
 {
   gpgme_data_read_cb_t read;
   gpgme_data_write_cb_t write;
   gpgme_data_seek_cb_t seek;
   gpgme_data_release_cb_t release;
 };
 typedef struct gpgme_data_cbs *gpgme_data_cbs_t;
 
 /* Read up to SIZE bytes into buffer BUFFER from the data object with
  * the handle DH.  Return the number of characters read, 0 on EOF and
  * -1 on error.  If an error occurs, errno is set.  */
 @API__SSIZE_T@ gpgme_data_read (gpgme_data_t dh, void *buffer, size_t size);
 
 /* Write up to SIZE bytes from buffer BUFFER to the data object with
  * the handle DH.  Return the number of characters written, or -1 on
  * error.  If an error occurs, errno is set.  */
 @API__SSIZE_T@ gpgme_data_write (gpgme_data_t dh, const void *buffer, size_t size);
 
 /* Set the current position from where the next read or write starts
  * in the data object with the handle DH to OFFSET, relativ to WHENCE.
  * Returns the new offset in bytes from the beginning of the data
  * object.  */
 @API__OFF_T@ gpgme_data_seek (gpgme_data_t dh, @API__OFF_T@ offset, int whence);
 
 /* Create a new data buffer and return it in R_DH.  */
 gpgme_error_t gpgme_data_new (gpgme_data_t *r_dh);
 
 /* Destroy the data buffer DH.  */
 void gpgme_data_release (gpgme_data_t dh);
 
 /* Create a new data buffer filled with SIZE bytes starting from
  * BUFFER.  If COPY is zero, copying is delayed until necessary, and
  * the data is taken from the original location when needed.  */
 gpgme_error_t gpgme_data_new_from_mem (gpgme_data_t *r_dh,
 				       const char *buffer, size_t size,
 				       int copy);
 
 /* Destroy the data buffer DH and return a pointer to its content.
  * The memory has be to released with gpgme_free() by the user.  It's
  * size is returned in R_LEN.  */
 char *gpgme_data_release_and_get_mem (gpgme_data_t dh, size_t *r_len);
 
 /* Release the memory returned by gpgme_data_release_and_get_mem() and
  * some other functions.  */
 void gpgme_free (void *buffer);
 
 gpgme_error_t gpgme_data_new_from_cbs (gpgme_data_t *dh,
 				       gpgme_data_cbs_t cbs,
 				       void *handle);
 
 gpgme_error_t gpgme_data_new_from_fd (gpgme_data_t *dh, int fd);
 
 gpgme_error_t gpgme_data_new_from_stream (gpgme_data_t *dh, FILE *stream);
 gpgme_error_t gpgme_data_new_from_estream (gpgme_data_t *r_dh,
                                            gpgrt_stream_t stream);
 
 /* Return the encoding attribute of the data buffer DH */
 gpgme_data_encoding_t gpgme_data_get_encoding (gpgme_data_t dh);
 
 /* Set the encoding attribute of data buffer DH to ENC */
 gpgme_error_t gpgme_data_set_encoding (gpgme_data_t dh,
 				       gpgme_data_encoding_t enc);
 
 /* Get the file name associated with the data object with handle DH, or
  * NULL if there is none.  */
 char *gpgme_data_get_file_name (gpgme_data_t dh);
 
 /* Set the file name associated with the data object with handle DH to
  * FILE_NAME.  */
 gpgme_error_t gpgme_data_set_file_name (gpgme_data_t dh,
 					const char *file_name);
 
 /* Set a flag for the data object DH.  See the manual for details.  */
 gpg_error_t gpgme_data_set_flag (gpgme_data_t dh,
                                  const char *name, const char *value);
 
 /* Try to identify the type of the data in DH.  */
 gpgme_data_type_t gpgme_data_identify (gpgme_data_t dh, int reserved);
 
 
 /* Create a new data buffer filled with the content of file FNAME.
  * COPY must be non-zero.  For delayed read, please use
  * gpgme_data_new_from_fd or gpgme_data_new_from_stream instead.  */
 gpgme_error_t gpgme_data_new_from_file (gpgme_data_t *r_dh,
 					const char *fname,
 					int copy);
 
 /* Create a new data buffer filled with LENGTH bytes starting from
  * OFFSET within the file FNAME or stream FP (exactly one must be
  * non-zero).  */
 gpgme_error_t gpgme_data_new_from_filepart (gpgme_data_t *r_dh,
 					    const char *fname, FILE *fp,
 					    @API__OFF_T@ offset, size_t length);
 
 /* Convenience function to do a gpgme_data_seek (dh, 0, SEEK_SET).  */
 gpgme_error_t gpgme_data_rewind (gpgme_data_t dh);
 
 
 
 /*
  * Key and trust functions.
  */
 
 /* Get the key with the fingerprint FPR from the crypto backend.  If
  * SECRET is true, get the secret key.  */
 gpgme_error_t gpgme_get_key (gpgme_ctx_t ctx, const char *fpr,
 			     gpgme_key_t *r_key, int secret);
 
 /* Create a dummy key to specify an email address.  */
 gpgme_error_t gpgme_key_from_uid (gpgme_key_t *key, const char *name);
 
 /* Acquire a reference to KEY.  */
 void gpgme_key_ref (gpgme_key_t key);
 
 /* Release a reference to KEY.  If this was the last one the key is
  * destroyed.  */
 void gpgme_key_unref (gpgme_key_t key);
 void gpgme_key_release (gpgme_key_t key);
 
 
 
 /*
  * Encryption.
  */
 
 /* An object to return results from an encryption operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_encrypt_result
 {
   /* The list of invalid recipients.  */
   gpgme_invalid_key_t invalid_recipients;
 };
 typedef struct _gpgme_op_encrypt_result *gpgme_encrypt_result_t;
 
 /* Retrieve a pointer to the result of the encrypt operation.  */
 gpgme_encrypt_result_t gpgme_op_encrypt_result (gpgme_ctx_t ctx);
 
 /* The valid encryption flags.  */
 typedef enum
   {
     GPGME_ENCRYPT_ALWAYS_TRUST = 1,
     GPGME_ENCRYPT_NO_ENCRYPT_TO = 2,
     GPGME_ENCRYPT_PREPARE = 4,
     GPGME_ENCRYPT_EXPECT_SIGN = 8,
     GPGME_ENCRYPT_NO_COMPRESS = 16,
     GPGME_ENCRYPT_SYMMETRIC = 32,
     GPGME_ENCRYPT_THROW_KEYIDS = 64,
     GPGME_ENCRYPT_WRAP = 128,
     GPGME_ENCRYPT_WANT_ADDRESS = 256
   }
 gpgme_encrypt_flags_t;
 
 /* Encrypt plaintext PLAIN within CTX for the recipients RECP and
  * store the resulting ciphertext in CIPHER.  */
 gpgme_error_t gpgme_op_encrypt_start (gpgme_ctx_t ctx, gpgme_key_t recp[],
 				      gpgme_encrypt_flags_t flags,
 				      gpgme_data_t plain,
                                       gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt (gpgme_ctx_t ctx, gpgme_key_t recp[],
 				gpgme_encrypt_flags_t flags,
 				gpgme_data_t plain,
                                 gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt_ext_start (gpgme_ctx_t ctx, gpgme_key_t recp[],
                                           const char *recpstring,
                                           gpgme_encrypt_flags_t flags,
                                           gpgme_data_t plain,
                                           gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt_ext (gpgme_ctx_t ctx, gpgme_key_t recp[],
                                     const char *recpstring,
                                     gpgme_encrypt_flags_t flags,
                                     gpgme_data_t plain,
                                     gpgme_data_t cipher);
 
 /* Encrypt plaintext PLAIN within CTX for the recipients RECP and
  * store the resulting ciphertext in CIPHER.  Also sign the ciphertext
  * with the signers in CTX.  */
 gpgme_error_t gpgme_op_encrypt_sign_start (gpgme_ctx_t ctx,
 					   gpgme_key_t recp[],
 					   gpgme_encrypt_flags_t flags,
 					   gpgme_data_t plain,
 					   gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt_sign (gpgme_ctx_t ctx, gpgme_key_t recp[],
 				     gpgme_encrypt_flags_t flags,
 				     gpgme_data_t plain,
                                      gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt_sign_ext_start (gpgme_ctx_t ctx,
                                                gpgme_key_t recp[],
                                                const char *recpstring,
                                                gpgme_encrypt_flags_t flags,
                                                gpgme_data_t plain,
                                                gpgme_data_t cipher);
 gpgme_error_t gpgme_op_encrypt_sign_ext (gpgme_ctx_t ctx, gpgme_key_t recp[],
                                          const char *recpstring,
                                          gpgme_encrypt_flags_t flags,
                                          gpgme_data_t plain,
                                          gpgme_data_t cipher);
 
 
 /*
  * Decryption.
  */
 
 /* An object to hold information about a recipient.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_recipient
 {
   struct _gpgme_recipient *next;
 
   /* The key ID of key for which the text was encrypted.  */
   char *keyid;
 
   /* Internal to GPGME, do not use.  */
   char _keyid[16 + 1];
 
   /* The public key algorithm of the recipient key.  */
   gpgme_pubkey_algo_t pubkey_algo;
 
   /* The status of the recipient.  */
   gpgme_error_t status;
 };
 typedef struct _gpgme_recipient *gpgme_recipient_t;
 
 
 /* An object to return results from a decryption operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_decrypt_result
 {
   char *unsupported_algorithm;
 
   /* Key should not have been used for encryption.  */
   unsigned int wrong_key_usage : 1;
 
   /* True if the message was encrypted in compliance to the de-vs
    * mode.  */
   unsigned int is_de_vs : 1;
 
   /* The message claims that the content is a MIME object.  */
   unsigned int is_mime : 1;
 
   /* The message was made by a legacy algorithm without any integrity
    * protection.  This might be an old but legitimate message. */
   unsigned int legacy_cipher_nomdc : 1;
 
   /* Internal to GPGME, do not use.  */
   int _unused : 28;
 
   gpgme_recipient_t recipients;
 
   /* The original file name of the plaintext message, if
    * available.  */
   char *file_name;
 
   /* A textual representation of the session key used to decrypt the
    * message, if available */
   char *session_key;
 
   /* A string with the symmetric encryption algorithm and mode using
    * the format "<algo>.<mode>".  */
   char *symkey_algo;
 };
 typedef struct _gpgme_op_decrypt_result *gpgme_decrypt_result_t;
 
 
 /* Retrieve a pointer to the result of the decrypt operation.  */
 gpgme_decrypt_result_t gpgme_op_decrypt_result (gpgme_ctx_t ctx);
 
 
 /* The valid decryption flags.  */
 typedef enum
   {
     GPGME_DECRYPT_VERIFY = 1,
     GPGME_DECRYPT_UNWRAP = 128
   }
 gpgme_decrypt_flags_t;
 
 
 /* Decrypt ciphertext CIPHER within CTX and store the resulting
  * plaintext in PLAIN.  */
 gpgme_error_t gpgme_op_decrypt_start (gpgme_ctx_t ctx, gpgme_data_t cipher,
 				      gpgme_data_t plain);
 gpgme_error_t gpgme_op_decrypt (gpgme_ctx_t ctx,
 				gpgme_data_t cipher, gpgme_data_t plain);
 
 /* Decrypt ciphertext CIPHER and make a signature verification within
  * CTX and store the resulting plaintext in PLAIN.  */
 gpgme_error_t gpgme_op_decrypt_verify_start (gpgme_ctx_t ctx,
 					     gpgme_data_t cipher,
 					     gpgme_data_t plain);
 gpgme_error_t gpgme_op_decrypt_verify (gpgme_ctx_t ctx, gpgme_data_t cipher,
 				       gpgme_data_t plain);
 
 /* Decrypt ciphertext CIPHER within CTX and store the resulting
  * plaintext in PLAIN.  With the flag GPGME_DECRYPT_VERIFY also do a
  * signature verification pn the plaintext.  */
 gpgme_error_t gpgme_op_decrypt_ext_start (gpgme_ctx_t ctx,
                                           gpgme_decrypt_flags_t flags,
                                           gpgme_data_t cipher,
                                           gpgme_data_t plain);
 gpgme_error_t gpgme_op_decrypt_ext (gpgme_ctx_t ctx,
                                     gpgme_decrypt_flags_t flags,
                                     gpgme_data_t cipher,
                                     gpgme_data_t plain);
 
 
 
 /*
  * Signing.
  */
 
 /* An object with signatures data.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_new_signature
 {
   struct _gpgme_new_signature *next;
 
   /* The type of the signature.  */
   gpgme_sig_mode_t type;
 
   /* The public key algorithm used to create the signature.  */
   gpgme_pubkey_algo_t pubkey_algo;
 
   /* The hash algorithm used to create the signature.  */
   gpgme_hash_algo_t hash_algo;
 
   /* Internal to GPGME, do not use.  Must be set to the same value as
    * CLASS below.  */
   unsigned long _obsolete_class;
 
   /* Signature creation time.  */
   long int timestamp;
 
   /* The fingerprint of the signature.  */
   char *fpr;
 
   /* Deprecated; use SIG_CLASS instead.  */
 #ifdef _GPGME_OBSOLETE_SOME_SYMBOLS
   unsigned int _obsolete_class_2;
 #else
   unsigned int class _GPGME_DEPRECATED_OUTSIDE_GPGME(0,4);
 #endif
 
   /* Crypto backend specific signature class.  */
   unsigned int sig_class;
 };
 typedef struct _gpgme_new_signature *gpgme_new_signature_t;
 
 
 /* An object to return results from a signing operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_sign_result
 {
   /* The list of invalid signers.  */
   gpgme_invalid_key_t invalid_signers;
   gpgme_new_signature_t signatures;
 };
 typedef struct _gpgme_op_sign_result *gpgme_sign_result_t;
 
 
 /* Retrieve a pointer to the result of the signing operation.  */
 gpgme_sign_result_t gpgme_op_sign_result (gpgme_ctx_t ctx);
 
 /* Sign the plaintext PLAIN and store the signature in SIG.  */
 gpgme_error_t gpgme_op_sign_start (gpgme_ctx_t ctx,
 				   gpgme_data_t plain, gpgme_data_t sig,
 				   gpgme_sig_mode_t mode);
 gpgme_error_t gpgme_op_sign (gpgme_ctx_t ctx,
 			     gpgme_data_t plain, gpgme_data_t sig,
 			     gpgme_sig_mode_t mode);
 
 
 /*
  * Verify.
  */
 
 /* Flags used for the SUMMARY field in a gpgme_signature_t.  */
 typedef enum
   {
     GPGME_SIGSUM_VALID       = 0x0001,  /* The signature is fully valid.  */
     GPGME_SIGSUM_GREEN       = 0x0002,  /* The signature is good.  */
     GPGME_SIGSUM_RED         = 0x0004,  /* The signature is bad.  */
     GPGME_SIGSUM_KEY_REVOKED = 0x0010,  /* One key has been revoked.  */
     GPGME_SIGSUM_KEY_EXPIRED = 0x0020,  /* One key has expired.  */
     GPGME_SIGSUM_SIG_EXPIRED = 0x0040,  /* The signature has expired.  */
     GPGME_SIGSUM_KEY_MISSING = 0x0080,  /* Can't verify: key missing.  */
     GPGME_SIGSUM_CRL_MISSING = 0x0100,  /* CRL not available.  */
     GPGME_SIGSUM_CRL_TOO_OLD = 0x0200,  /* Available CRL is too old.  */
     GPGME_SIGSUM_BAD_POLICY  = 0x0400,  /* A policy was not met.  */
     GPGME_SIGSUM_SYS_ERROR   = 0x0800,  /* A system error occurred.  */
     GPGME_SIGSUM_TOFU_CONFLICT=0x1000   /* Tofu conflict detected.  */
   }
 gpgme_sigsum_t;
 
 
 /* An object to hold the verification status of a signature.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_signature
 {
   struct _gpgme_signature *next;
 
   /* A summary of the signature status.  */
   gpgme_sigsum_t summary;
 
   /* The fingerprint of the signature.  This can be a subkey.  */
   char *fpr;
 
   /* The status of the signature.  */
   gpgme_error_t status;
 
   /* Notation data and policy URLs.  */
   gpgme_sig_notation_t notations;
 
   /* Signature creation time.  */
   unsigned long timestamp;
 
   /* Signature expiration time or 0.  */
   unsigned long exp_timestamp;
 
   /* Key should not have been used for signing.  */
   unsigned int wrong_key_usage : 1;
 
   /* PKA status: 0 = not available, 1 = bad, 2 = okay, 3 = RFU. */
   unsigned int pka_trust : 2;
 
   /* Validity has been verified using the chain model. */
   unsigned int chain_model : 1;
 
   /* True if the signature is in compliance to the de-vs mode.  */
   unsigned int is_de_vs : 1;
 
   /* Internal to GPGME, do not use.  */
   int _unused : 27;
 
   gpgme_validity_t validity;
   gpgme_error_t validity_reason;
 
   /* The public key algorithm used to create the signature.  */
   gpgme_pubkey_algo_t pubkey_algo;
 
   /* The hash algorithm used to create the signature.  */
   gpgme_hash_algo_t hash_algo;
 
   /* The mailbox from the PKA information or NULL. */
   char *pka_address;
 
   /* If non-NULL, a possible incomplete key object with the data
    * available for the signature.  */
   gpgme_key_t key;
 };
 typedef struct _gpgme_signature *gpgme_signature_t;
 
 
 /* An object to return the results of a verify operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_verify_result
 {
   gpgme_signature_t signatures;
 
   /* The original file name of the plaintext message, if available.
    * Warning: This information is not covered by the signature.  */
   char *file_name;
 
   /* The message claims that the content is a MIME object.  */
   /* Warning: This flag is not covered by the signature.  */
   unsigned int is_mime : 1;
 
   /* Internal to GPGME; do not use.  */
   unsigned int _unused : 31;
 };
 typedef struct _gpgme_op_verify_result *gpgme_verify_result_t;
 
 
 /* Retrieve a pointer to the result of the verify operation.  */
 gpgme_verify_result_t gpgme_op_verify_result (gpgme_ctx_t ctx);
 
 /* Verify within CTX that SIG is a valid signature for TEXT.  */
 gpgme_error_t gpgme_op_verify_start (gpgme_ctx_t ctx, gpgme_data_t sig,
 				     gpgme_data_t signed_text,
 				     gpgme_data_t plaintext);
 gpgme_error_t gpgme_op_verify (gpgme_ctx_t ctx, gpgme_data_t sig,
 			       gpgme_data_t signed_text,
 			       gpgme_data_t plaintext);
 
 
 /*
  * Import/Export
  */
 
 #define GPGME_IMPORT_NEW	1  /* The key was new.  */
 #define GPGME_IMPORT_UID	2  /* The key contained new user IDs.  */
 #define GPGME_IMPORT_SIG	4  /* The key contained new signatures.  */
 #define GPGME_IMPORT_SUBKEY	8  /* The key contained new sub keys.  */
 #define GPGME_IMPORT_SECRET    16  /* The key contained a secret key.  */
 
 
 /* An object to hold results for one imported key.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_import_status
 {
   struct _gpgme_import_status *next;
 
   /* Fingerprint.  */
   char *fpr;
 
   /* If a problem occurred, the reason why the key could not be
      imported.  Otherwise GPGME_No_Error.  */
   gpgme_error_t result;
 
   /* The result of the import, the GPGME_IMPORT_* values bit-wise
      ORed.  0 means the key was already known and no new components
      have been added.  */
   unsigned int status;
 };
 typedef struct _gpgme_import_status *gpgme_import_status_t;
 
 
 /* Import result object.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_import_result
 {
   /* Number of considered keys.  */
   int considered;
 
   /* Keys without user ID.  */
   int no_user_id;
 
   /* Imported keys.  */
   int imported;
 
   /* Imported RSA keys.  */
   int imported_rsa;
 
   /* Unchanged keys.  */
   int unchanged;
 
   /* Number of new user ids.  */
   int new_user_ids;
 
   /* Number of new sub keys.  */
   int new_sub_keys;
 
   /* Number of new signatures.  */
   int new_signatures;
 
   /* Number of new revocations.  */
   int new_revocations;
 
   /* Number of secret keys read.  */
   int secret_read;
 
   /* Number of secret keys imported.  */
   int secret_imported;
 
   /* Number of secret keys unchanged.  */
   int secret_unchanged;
 
   /* Number of new keys skipped.  */
   int skipped_new_keys;
 
   /* Number of keys not imported.  */
   int not_imported;
 
   /* List of keys for which an import was attempted.  */
   gpgme_import_status_t imports;
 
   /* Number of v3 keys skipped.  */
   int skipped_v3_keys;
 };
 typedef struct _gpgme_op_import_result *gpgme_import_result_t;
 
 
 /* Retrieve a pointer to the result of the import operation.  */
 gpgme_import_result_t gpgme_op_import_result (gpgme_ctx_t ctx);
 
 /* Import the key in KEYDATA into the keyring.  */
 gpgme_error_t gpgme_op_import_start (gpgme_ctx_t ctx, gpgme_data_t keydata);
 gpgme_error_t gpgme_op_import (gpgme_ctx_t ctx, gpgme_data_t keydata);
 
 /* Import the keys from the array KEYS into the keyring.  */
 gpgme_error_t gpgme_op_import_keys_start (gpgme_ctx_t ctx, gpgme_key_t keys[]);
 gpgme_error_t gpgme_op_import_keys (gpgme_ctx_t ctx, gpgme_key_t keys[]);
 
 
 /* Export the keys found by PATTERN into KEYDATA.  */
 gpgme_error_t gpgme_op_export_start (gpgme_ctx_t ctx, const char *pattern,
 				     gpgme_export_mode_t mode,
 				     gpgme_data_t keydata);
 gpgme_error_t gpgme_op_export (gpgme_ctx_t ctx, const char *pattern,
 			       gpgme_export_mode_t mode,
                                gpgme_data_t keydata);
 
 gpgme_error_t gpgme_op_export_ext_start (gpgme_ctx_t ctx,
 					 const char *pattern[],
 					 gpgme_export_mode_t mode,
 					 gpgme_data_t keydata);
 gpgme_error_t gpgme_op_export_ext (gpgme_ctx_t ctx, const char *pattern[],
 				   gpgme_export_mode_t mode,
 				   gpgme_data_t keydata);
 
 /* Export the keys from the array KEYS into KEYDATA.  */
 gpgme_error_t gpgme_op_export_keys_start (gpgme_ctx_t ctx,
                                           gpgme_key_t keys[],
                                           gpgme_export_mode_t mode,
                                           gpgme_data_t keydata);
 gpgme_error_t gpgme_op_export_keys (gpgme_ctx_t ctx,
                                     gpgme_key_t keys[],
                                     gpgme_export_mode_t mode,
                                     gpgme_data_t keydata);
 
 
 
 /*
  * Key generation.
  */
 
 /* Flags for the key creation functions.  */
 #define GPGME_CREATE_SIGN       (1 << 0)  /* Allow usage: signing.     */
 #define GPGME_CREATE_ENCR       (1 << 1)  /* Allow usage: encryption.  */
 #define GPGME_CREATE_CERT       (1 << 2)  /* Allow usage: certification.  */
 #define GPGME_CREATE_AUTH       (1 << 3)  /* Allow usage: authentication.  */
 #define GPGME_CREATE_NOPASSWD   (1 << 7)  /* Create w/o passphrase.    */
 #define GPGME_CREATE_SELFSIGNED (1 << 8)  /* Create self-signed cert.  */
 #define GPGME_CREATE_NOSTORE    (1 << 9)  /* Do not store the key.     */
 #define GPGME_CREATE_WANTPUB    (1 << 10) /* Return the public key.    */
 #define GPGME_CREATE_WANTSEC    (1 << 11) /* Return the secret key.    */
 #define GPGME_CREATE_FORCE      (1 << 12) /* Force creation.           */
 #define GPGME_CREATE_NOEXPIRE   (1 << 13) /* Create w/o expiration.    */
 
 
 /* An object to return result from a key generation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_genkey_result
 {
   /* A primary key was generated.  */
   unsigned int primary : 1;
 
   /* A sub key was generated.  */
   unsigned int sub : 1;
 
   /* A user id was generated.  */
   unsigned int uid : 1;
 
   /* Internal to GPGME, do not use.  */
   unsigned int _unused : 29;
 
   /* The fingerprint of the generated key.  */
   char *fpr;
 
   /* A memory data object with the created public key.  Only set when
    * GPGME_CREATE_WANTPUB has been used. */
   gpgme_data_t pubkey;
 
   /* A memory data object with the created secret key.  Only set when
    * GPGME_CREATE_WANTSEC has been used. */
   gpgme_data_t seckey;
 };
 typedef struct _gpgme_op_genkey_result *gpgme_genkey_result_t;
 
 
 /* Generate a new keypair and add it to the keyring.  PUBKEY and
  * SECKEY should be null for now.  PARMS specifies what keys should be
  * generated.  */
 gpgme_error_t gpgme_op_genkey_start (gpgme_ctx_t ctx, const char *parms,
 				     gpgme_data_t pubkey, gpgme_data_t seckey);
 gpgme_error_t gpgme_op_genkey (gpgme_ctx_t ctx, const char *parms,
 			       gpgme_data_t pubkey, gpgme_data_t seckey);
 
 /* Generate a key pair using the modern interface.  */
 gpgme_error_t gpgme_op_createkey_start (gpgme_ctx_t ctx,
                                         const char *userid,
                                         const char *algo,
                                         unsigned long reserved,
                                         unsigned long expires,
                                         gpgme_key_t certkey,
                                         unsigned int flags);
 gpgme_error_t gpgme_op_createkey       (gpgme_ctx_t ctx,
                                         const char *userid,
                                         const char *algo,
                                         unsigned long reserved,
                                         unsigned long expires,
                                         gpgme_key_t certkey,
                                         unsigned int flags);
 /* Add a new subkey to KEY.  */
 gpgme_error_t gpgme_op_createsubkey_start (gpgme_ctx_t ctx,
                                            gpgme_key_t key,
                                            const char *algo,
                                            unsigned long reserved,
                                            unsigned long expires,
                                            unsigned int flags);
 gpgme_error_t gpgme_op_createsubkey       (gpgme_ctx_t ctx,
                                            gpgme_key_t key,
                                            const char *algo,
                                            unsigned long reserved,
                                            unsigned long expires,
                                            unsigned int flags);
 
 /* Add USERID to an existing KEY.  */
 gpgme_error_t gpgme_op_adduid_start (gpgme_ctx_t ctx,
                                      gpgme_key_t key, const char *userid,
                                      unsigned int reserved);
 gpgme_error_t gpgme_op_adduid       (gpgme_ctx_t ctx,
                                      gpgme_key_t key, const char *userid,
                                      unsigned int reserved);
 
 /* Revoke a USERID from a KEY.  */
 gpgme_error_t gpgme_op_revuid_start (gpgme_ctx_t ctx,
                                      gpgme_key_t key, const char *userid,
                                      unsigned int reserved);
 gpgme_error_t gpgme_op_revuid       (gpgme_ctx_t ctx,
                                      gpgme_key_t key, const char *userid,
                                      unsigned int reserved);
 
 /* Set a flag on the USERID of KEY.  See the manual for supported flags.  */
 gpgme_error_t gpgme_op_set_uid_flag_start (gpgme_ctx_t ctx,
                                            gpgme_key_t key, const char *userid,
                                            const char *name, const char *value);
 gpgme_error_t gpgme_op_set_uid_flag       (gpgme_ctx_t ctx,
                                            gpgme_key_t key, const char *userid,
                                            const char *name, const char *value);
 
 /* Change the expiry of a key.  */
 gpgme_error_t gpgme_op_setexpire_start (gpgme_ctx_t ctx,
                                         gpgme_key_t key, unsigned long expires,
                                         const char *subfprs, unsigned int reserved);
 gpgme_error_t gpgme_op_setexpire       (gpgme_ctx_t ctx,
                                         gpgme_key_t key, unsigned long expires,
                                         const char *subfprs, unsigned int reserved);
 
 /* Retrieve a pointer to the result of a genkey, createkey, or
  * createsubkey operation.  */
 gpgme_genkey_result_t gpgme_op_genkey_result (gpgme_ctx_t ctx);
 
 
 /* Delete KEY from the keyring.  If ALLOW_SECRET is non-zero, secret
  * keys are also deleted.  */
 gpgme_error_t gpgme_op_delete_start (gpgme_ctx_t ctx, const gpgme_key_t key,
 				     int allow_secret);
 gpgme_error_t gpgme_op_delete (gpgme_ctx_t ctx, const gpgme_key_t key,
 			       int allow_secret);
 
 /* Flags for the key delete functions.  */
 #define GPGME_DELETE_ALLOW_SECRET (1 << 0)  /* Also delete secret key.     */
 #define GPGME_DELETE_FORCE        (1 << 1)  /* Do not ask user to confirm.  */
 
 gpgme_error_t gpgme_op_delete_ext_start (gpgme_ctx_t ctx, const gpgme_key_t key,
 					 unsigned int flags);
 gpgme_error_t gpgme_op_delete_ext (gpgme_ctx_t ctx, const gpgme_key_t key,
 				   unsigned int flags);
 
 
 /*
  * Key signing interface
  */
 
 /* Flags for the key signing functions.  */
 #define GPGME_KEYSIGN_LOCAL     (1 << 7)  /* Create a local signature.  */
 #define GPGME_KEYSIGN_LFSEP     (1 << 8)  /* Indicate LF separated user ids. */
 #define GPGME_KEYSIGN_NOEXPIRE  (1 << 9)  /* Force no expiration.  */
 #define GPGME_KEYSIGN_FORCE     (1 << 10) /* Force creation.  */
 
 
 /* Sign the USERID of KEY using the current set of signers.  */
 gpgme_error_t gpgme_op_keysign_start (gpgme_ctx_t ctx,
                                       gpgme_key_t key, const char *userid,
                                       unsigned long expires,
                                       unsigned int flags);
 gpgme_error_t gpgme_op_keysign       (gpgme_ctx_t ctx,
                                       gpgme_key_t key, const char *userid,
                                       unsigned long expires,
                                       unsigned int flags);
 
 
 /* Flags for the signature revoking functions.  */
 #define GPGME_REVSIG_LFSEP   (1 << 8)  /* Indicate LF separated user ids. */
 
 /* Revoke the signatures made with SIGNING_KEY on the USERID(s) of KEY.  */
 gpgme_error_t gpgme_op_revsig_start (gpgme_ctx_t ctx,
                                      gpgme_key_t key,
                                      gpgme_key_t signing_key,
                                      const char *userid,
                                      unsigned int flags);
 gpgme_error_t gpgme_op_revsig       (gpgme_ctx_t ctx,
                                      gpgme_key_t key,
                                      gpgme_key_t signing_key,
                                      const char *userid,
                                      unsigned int flags);
 
 
 /*
  * Key edit interface
  */
 
 /* Flags to select the mode of the interact.  */
 #define GPGME_INTERACT_CARD   (1 << 0)  /* Use --card-edit mode. */
 
 
 /* Edit the KEY.  Send status and command requests to FNC and
    output of edit commands to OUT.  */
 gpgme_error_t gpgme_op_interact_start (gpgme_ctx_t ctx,
                                        gpgme_key_t key,
                                        unsigned int flags,
                                        gpgme_interact_cb_t fnc,
                                        void *fnc_value,
                                        gpgme_data_t out);
 gpgme_error_t gpgme_op_interact (gpgme_ctx_t ctx, gpgme_key_t key,
                                  unsigned int flags,
                                  gpgme_interact_cb_t fnc,
                                  void *fnc_value,
                                  gpgme_data_t out);
 
 
 /* Set the Tofu policy of KEY to POLCIY.  */
 gpgme_error_t gpgme_op_tofu_policy_start (gpgme_ctx_t ctx,
                                           gpgme_key_t key,
                                           gpgme_tofu_policy_t policy);
 gpgme_error_t gpgme_op_tofu_policy       (gpgme_ctx_t ctx,
                                           gpgme_key_t key,
                                           gpgme_tofu_policy_t policy);
 
 
 
 
 /*
  * Key listing
  */
 
 /* An object to return results from a key listing operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_keylist_result
 {
   unsigned int truncated : 1;
 
   /* Internal to GPGME, do not use.  */
   unsigned int _unused : 31;
 };
 typedef struct _gpgme_op_keylist_result *gpgme_keylist_result_t;
 
 /* Retrieve a pointer to the result of the key listing operation.  */
 gpgme_keylist_result_t gpgme_op_keylist_result (gpgme_ctx_t ctx);
 
 /* Start a keylist operation within CTX, searching for keys which
  * match PATTERN.  If SECRET_ONLY is true, only secret keys are
  * returned.  */
 gpgme_error_t gpgme_op_keylist_start (gpgme_ctx_t ctx, const char *pattern,
 				      int secret_only);
 gpgme_error_t gpgme_op_keylist_ext_start (gpgme_ctx_t ctx,
 					  const char *pattern[],
 					  int secret_only, int reserved);
 
 /* List the keys contained in DATA.  */
 gpgme_error_t gpgme_op_keylist_from_data_start (gpgme_ctx_t ctx,
                                                 gpgme_data_t data,
                                                 int reserved);
 
 /* Return the next key from the keylist in R_KEY.  */
 gpgme_error_t gpgme_op_keylist_next (gpgme_ctx_t ctx, gpgme_key_t *r_key);
 
 /* Terminate a pending keylist operation within CTX.  */
 gpgme_error_t gpgme_op_keylist_end (gpgme_ctx_t ctx);
 
 
 
 /*
  * Protecting keys
  */
 
 /* Change the passphrase for KEY.  FLAGS is reserved for future use
  * and must be passed as 0.  */
 gpgme_error_t gpgme_op_passwd_start (gpgme_ctx_t ctx, gpgme_key_t key,
                                      unsigned int flags);
 gpgme_error_t gpgme_op_passwd (gpgme_ctx_t ctx, gpgme_key_t key,
                                unsigned int flags);
 
 
 
 /*
  * Trust items and operations.  DO NOT USE.
  * Note: This does not work because the experimental support in the
  * GnuPG engine has been removed a very long time; for API and ABI
  * compatibilty we keep the functions but let them return an error.
  * See https://dev.gnupg.org/T4834
  */
 struct _gpgme_trust_item
 {
   unsigned int _refs;
   char *keyid;
   char _keyid[16 + 1];
   int type;
   int level;
   char *owner_trust;
   char _owner_trust[2];
   char *validity;
   char _validity[2];
   char *name;
 };
 typedef struct _gpgme_trust_item *gpgme_trust_item_t;
 gpgme_error_t gpgme_op_trustlist_start (gpgme_ctx_t ctx,
 					const char *pattern, int max_level);
 gpgme_error_t gpgme_op_trustlist_next (gpgme_ctx_t ctx,
 				       gpgme_trust_item_t *r_item);
 gpgme_error_t gpgme_op_trustlist_end (gpgme_ctx_t ctx);
 void gpgme_trust_item_ref (gpgme_trust_item_t item);
 void gpgme_trust_item_unref (gpgme_trust_item_t item);
 
 
 
 /*
  * Audit log
  */
 
 /* Return the auditlog for the current session.  This may be called
    after a successful or failed operation.  If no audit log is
    available GPG_ERR_NO_DATA is returned.  */
 gpgme_error_t gpgme_op_getauditlog_start (gpgme_ctx_t ctx, gpgme_data_t output,
                                           unsigned int flags);
 gpgme_error_t gpgme_op_getauditlog (gpgme_ctx_t ctx, gpgme_data_t output,
                                     unsigned int flags);
 
 
 
 /*
  * Spawn interface
  */
 
 /* Flags for the spawn operations.  */
 #define GPGME_SPAWN_DETACHED      1
 #define GPGME_SPAWN_ALLOW_SET_FG  2
 #define GPGME_SPAWN_SHOW_WINDOW   4
 
 
 /* Run the command FILE with the arguments in ARGV.  Connect stdin to
  * DATAIN, stdout to DATAOUT, and STDERR to DATAERR.  If one the data
  * streams is NULL, connect to /dev/null instead.  */
 gpgme_error_t gpgme_op_spawn_start (gpgme_ctx_t ctx,
                                     const char *file, const char *argv[],
                                     gpgme_data_t datain,
                                     gpgme_data_t dataout, gpgme_data_t dataerr,
                                     unsigned int flags);
 gpgme_error_t gpgme_op_spawn (gpgme_ctx_t ctx,
                               const char *file, const char *argv[],
                               gpgme_data_t datain,
                               gpgme_data_t dataout, gpgme_data_t dataerr,
                               unsigned int flags);
 
 
 /*
  * Low-level Assuan protocol access.
  */
 
 typedef gpgme_error_t (*gpgme_assuan_data_cb_t)
      (void *opaque, const void *data, size_t datalen);
 
 typedef gpgme_error_t (*gpgme_assuan_inquire_cb_t)
      (void *opaque, const char *name, const char *args,
       gpgme_data_t *r_data);
 
 typedef gpgme_error_t (*gpgme_assuan_status_cb_t)
      (void *opaque, const char *status, const char *args);
 
 /* Send the Assuan COMMAND and return results via the callbacks.
  * Asynchronous variant. */
 gpgme_error_t gpgme_op_assuan_transact_start (gpgme_ctx_t ctx,
                                               const char *command,
                                               gpgme_assuan_data_cb_t data_cb,
                                               void *data_cb_value,
                                               gpgme_assuan_inquire_cb_t inq_cb,
                                               void *inq_cb_value,
                                               gpgme_assuan_status_cb_t stat_cb,
                                               void *stat_cb_value);
 
 /* Send the Assuan COMMAND and return results via the callbacks.
  * Synchronous variant. */
 gpgme_error_t gpgme_op_assuan_transact_ext (gpgme_ctx_t ctx,
 					    const char *command,
 					    gpgme_assuan_data_cb_t data_cb,
 					    void *data_cb_value,
 					    gpgme_assuan_inquire_cb_t inq_cb,
 					    void *inq_cb_value,
 					    gpgme_assuan_status_cb_t stat_cb,
 					    void *stat_cb_value,
 					    gpgme_error_t *op_err);
 
 
 /*
  * Crypto container support.
  */
 
 /* An object to return results from a VFS mount operation.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_vfs_mount_result
 {
   char *mount_dir;
 };
 typedef struct _gpgme_op_vfs_mount_result *gpgme_vfs_mount_result_t;
 
 gpgme_vfs_mount_result_t gpgme_op_vfs_mount_result (gpgme_ctx_t ctx);
 
 /* The container is automatically unmounted when the context is reset
  * or destroyed.  Transmission errors are returned directly,
  * operational errors are returned in OP_ERR.  */
 gpgme_error_t gpgme_op_vfs_mount (gpgme_ctx_t ctx, const char *container_file,
 				  const char *mount_dir, unsigned int flags,
 				  gpgme_error_t *op_err);
 
 gpgme_error_t gpgme_op_vfs_create (gpgme_ctx_t ctx, gpgme_key_t recp[],
 				   const char *container_file,
 				   unsigned int flags, gpgme_error_t *op_err);
 
 
 /*
  * Interface to gpgconf(1).
  */
 
 /* The expert level at which a configuration option or group of
  * options should be displayed.  See the gpgconf(1) documentation for
  * more details.  */
 typedef enum
   {
     GPGME_CONF_BASIC = 0,
     GPGME_CONF_ADVANCED = 1,
     GPGME_CONF_EXPERT = 2,
     GPGME_CONF_INVISIBLE = 3,
     GPGME_CONF_INTERNAL = 4
   }
 gpgme_conf_level_t;
 
 
 /* The data type of a configuration option argument.  See the gpgconf(1)
  * documentation for more details.  */
 typedef enum
   {
     /* Basic types.  */
     GPGME_CONF_NONE = 0,
     GPGME_CONF_STRING = 1,
     GPGME_CONF_INT32 = 2,
     GPGME_CONF_UINT32 = 3,
 
     /* Complex types.  */
     GPGME_CONF_FILENAME = 32,
     GPGME_CONF_LDAP_SERVER = 33,
     GPGME_CONF_KEY_FPR = 34,
     GPGME_CONF_PUB_KEY = 35,
     GPGME_CONF_SEC_KEY = 36,
     GPGME_CONF_ALIAS_LIST = 37
   }
 gpgme_conf_type_t;
 
 /* For now, compatibility.  */
 #define GPGME_CONF_PATHNAME GPGME_CONF_FILENAME
 
 
 /* This represents a single argument for a configuration option.
  * Which of the members of value is used depends on the ALT_TYPE.  */
 typedef struct gpgme_conf_arg
 {
   struct gpgme_conf_arg *next;
   /* True if the option appears without an (optional) argument.  */
   unsigned int no_arg;
   union
   {
     unsigned int count;
     unsigned int uint32;
     int int32;
     char *string;
   } value;
 } *gpgme_conf_arg_t;
 
 
 /* The flags of a configuration option.  See the gpgconf
  * documentation for details.  */
 #define GPGME_CONF_GROUP	(1 << 0)
 #define GPGME_CONF_OPTIONAL	(1 << 1)
 #define GPGME_CONF_LIST		(1 << 2)
 #define GPGME_CONF_RUNTIME	(1 << 3)
 #define GPGME_CONF_DEFAULT	(1 << 4)
 #define GPGME_CONF_DEFAULT_DESC	(1 << 5)
 #define GPGME_CONF_NO_ARG_DESC	(1 << 6)
 #define GPGME_CONF_NO_CHANGE	(1 << 7)
 
 
 /* The representation of a single configuration option.  See the
  * gpg-conf documentation for details.  */
 typedef struct gpgme_conf_opt
 {
   struct gpgme_conf_opt *next;
 
   /* The option name.  */
   char *name;
 
   /* The flags for this option.  */
   unsigned int flags;
 
   /* The level of this option.  */
   gpgme_conf_level_t level;
 
   /* The localized description of this option.  */
   char *description;
 
   /* The type and alternate type of this option.  */
   gpgme_conf_type_t type;
   gpgme_conf_type_t alt_type;
 
   /* The localized (short) name of the argument, if any.  */
   char *argname;
 
   /* The default value.  */
   gpgme_conf_arg_t default_value;
   char *default_description;
 
   /* The default value if the option is not set.  */
   gpgme_conf_arg_t no_arg_value;
   char *no_arg_description;
 
   /* The current value if the option is set.  */
   gpgme_conf_arg_t value;
 
   /* The new value, if any.  NULL means reset to default.  */
   int change_value;
   gpgme_conf_arg_t new_value;
 
   /* Free for application use.  */
   void *user_data;
 } *gpgme_conf_opt_t;
 
 
 /* The representation of a component that can be configured.  See the
  * gpg-conf documentation for details.  */
 typedef struct gpgme_conf_comp
 {
   struct gpgme_conf_comp *next;
 
   /* Internal to GPGME, do not use!  */
   gpgme_conf_opt_t *_last_opt_p;
 
   /* The component name.  */
   char *name;
 
   /* A human-readable description for the component.  */
   char *description;
 
   /* The program name (an absolute path to the program).  */
   char *program_name;
 
   /* A linked list of options for this component.  */
   struct gpgme_conf_opt *options;
 } *gpgme_conf_comp_t;
 
 
 /* Allocate a new gpgme_conf_arg_t.  If VALUE is NULL, a "no arg
  * default" is prepared.  If type is a string type, VALUE should point
  * to the string.  Else, it should point to an unsigned or signed
  * integer respectively.  */
 gpgme_error_t gpgme_conf_arg_new (gpgme_conf_arg_t *arg_p,
 				  gpgme_conf_type_t type, const void *value);
 
 /* This also releases all chained argument structures!  */
 void gpgme_conf_arg_release (gpgme_conf_arg_t arg, gpgme_conf_type_t type);
 
 /* Register a change for the value of OPT to ARG.  If RESET is 1 (do
  * not use any values but 0 or 1), ARG is ignored and the option is
  * not changed (reverting a previous change).  Otherwise, if ARG is
  * NULL, the option is cleared or reset to its default. The change
  * is done with gpgconf's --runtime option to immediately take effect. */
 gpgme_error_t gpgme_conf_opt_change (gpgme_conf_opt_t opt, int reset,
 				     gpgme_conf_arg_t arg);
 
 /* Release a set of configurations.  */
 void gpgme_conf_release (gpgme_conf_comp_t conf);
 
 /* Retrieve the current configurations.  */
 gpgme_error_t gpgme_op_conf_load (gpgme_ctx_t ctx, gpgme_conf_comp_t *conf_p);
 
 /* Save the configuration of component comp.  This function does not
    follow chained components!  */
 gpgme_error_t gpgme_op_conf_save (gpgme_ctx_t ctx, gpgme_conf_comp_t comp);
 
 /* Retrieve the configured directory.  */
 gpgme_error_t gpgme_op_conf_dir(gpgme_ctx_t ctx, const char *what,
 				char **result);
 
 
 /* Information about software versions.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 typedef struct _gpgme_op_query_swdb_result
 {
   /* RFU */
   struct _gpgme_op_query_swdb_result *next;
 
   /* The name of the package (e.g. "gpgme", "gnupg") */
   char *name;
 
   /* The version number of the installed version.  */
   char *iversion;
 
   /* The time the online info was created.  */
   unsigned long created;
 
   /* The time the online info was retrieved.  */
   unsigned long retrieved;
 
   /* This bit is set if an error occured or some of the information
    * in this structure may not be set.  */
   unsigned int warning : 1;
 
   /* An update is available.  */
   unsigned int update : 1;
 
   /* The update is important.  */
   unsigned int urgent : 1;
 
   /* No information at all available.  */
   unsigned int noinfo : 1;
 
   /* The package name is not known. */
   unsigned int unknown : 1;
 
   /* The information here is too old.  */
   unsigned int tooold : 1;
 
   /* Other error.  */
   unsigned int error : 1;
 
   unsigned int _reserved : 25;
 
   /* The version number of the latest released version.  */
   char *version;
 
   /* The release date of that version.  */
   unsigned long reldate;
 
 } *gpgme_query_swdb_result_t;
 
 
 /* Run the gpgconf --query-swdb command.  */
 gpgme_error_t gpgme_op_query_swdb (gpgme_ctx_t ctx,
                                    const char *name, const char *iversion,
                                    unsigned int reserved);
 
 /* Return the result from the last query_swdb operation.  */
 gpgme_query_swdb_result_t gpgme_op_query_swdb_result (gpgme_ctx_t ctx);
 
 
 
 
 /*
  * Various functions.
  */
 
 /* Set special global flags; consult the manual before use.  */
 int gpgme_set_global_flag (const char *name, const char *value);
 
 /* Check that the library fulfills the version requirement.  Note:
  * This is here only for the case where a user takes a pointer from
  * the old version of this function.  The new version and macro for
  * run-time checks are below.  */
 const char *gpgme_check_version (const char *req_version);
 
 /* Do not call this directly; use the macro below.  */
 const char *gpgme_check_version_internal (const char *req_version,
 					  size_t offset_sig_validity);
 
 /* Check that the library fulfills the version requirement and check
  * for struct layout mismatch involving bitfields.  */
 #define gpgme_check_version(req_version)				\
   gpgme_check_version_internal (req_version,				\
 				offsetof (struct _gpgme_signature, validity))
 
 /* Return the default values for various directories.  */
 const char *gpgme_get_dirinfo (const char *what);
 
 /* Get the information about the configured and installed engines.  A
  * pointer to the first engine in the statically allocated linked list
  * is returned in *INFO.  If an error occurs, it is returned.  The
  * returned data is valid until the next gpgme_set_engine_info.  */
 gpgme_error_t gpgme_get_engine_info (gpgme_engine_info_t *engine_info);
 
 /* Set the default engine info for the protocol PROTO to the file name
  * FILE_NAME and the home directory HOME_DIR.  */
 gpgme_error_t gpgme_set_engine_info (gpgme_protocol_t proto,
 				     const char *file_name,
 				     const char *home_dir);
 
 /* Verify that the engine implementing PROTO is installed and
  * available.  */
 gpgme_error_t gpgme_engine_check_version (gpgme_protocol_t proto);
 
 
 /* Reference counting for result objects.  */
 void gpgme_result_ref (void *result);
 void gpgme_result_unref (void *result);
 
 /* Return a public key algorithm string (e.g. "rsa2048").  Caller must
  * free using gpgme_free.  */
 char *gpgme_pubkey_algo_string (gpgme_subkey_t subkey);
 
 /* Return a statically allocated string with the name of the public
  * key algorithm ALGO, or NULL if that name is not known.  */
 const char *gpgme_pubkey_algo_name (gpgme_pubkey_algo_t algo);
 
 /* Return a statically allocated string with the name of the hash
  * algorithm ALGO, or NULL if that name is not known.  */
 const char *gpgme_hash_algo_name (gpgme_hash_algo_t algo);
 
 /* Return the addr-spec from a user id.  Caller must free the result
  * with gpgme_free. */
 char *gpgme_addrspec_from_uid (const char *uid);
 
 
 
 /*
  * Deprecated types, constants and functions.
  */
 
 /* This is a former experimental only features.  The constant is
  * provided to not break existing code in the compiler phase.  */
 #define GPGME_EXPORT_MODE_NOUID               128  /* Do not use! */
 
 
 /* The possible stati for gpgme_op_edit.  The use of that function and
  * these status codes are deprecated in favor of gpgme_op_interact. */
 typedef enum
   {
     GPGME_STATUS_EOF = 0,
     /* mkstatus processing starts here */
     GPGME_STATUS_ENTER = 1,
     GPGME_STATUS_LEAVE = 2,
     GPGME_STATUS_ABORT = 3,
 
     GPGME_STATUS_GOODSIG = 4,
     GPGME_STATUS_BADSIG = 5,
     GPGME_STATUS_ERRSIG = 6,
 
     GPGME_STATUS_BADARMOR = 7,
 
     GPGME_STATUS_RSA_OR_IDEA = 8,      /* (legacy) */
     GPGME_STATUS_KEYEXPIRED = 9,
     GPGME_STATUS_KEYREVOKED = 10,
 
     GPGME_STATUS_TRUST_UNDEFINED = 11,
     GPGME_STATUS_TRUST_NEVER = 12,
     GPGME_STATUS_TRUST_MARGINAL = 13,
     GPGME_STATUS_TRUST_FULLY = 14,
     GPGME_STATUS_TRUST_ULTIMATE = 15,
 
     GPGME_STATUS_SHM_INFO = 16,        /* (legacy) */
     GPGME_STATUS_SHM_GET = 17,         /* (legacy) */
     GPGME_STATUS_SHM_GET_BOOL = 18,    /* (legacy) */
     GPGME_STATUS_SHM_GET_HIDDEN = 19,  /* (legacy) */
 
     GPGME_STATUS_NEED_PASSPHRASE = 20,
     GPGME_STATUS_VALIDSIG = 21,
     GPGME_STATUS_SIG_ID = 22,
     GPGME_STATUS_ENC_TO = 23,
     GPGME_STATUS_NODATA = 24,
     GPGME_STATUS_BAD_PASSPHRASE = 25,
     GPGME_STATUS_NO_PUBKEY = 26,
     GPGME_STATUS_NO_SECKEY = 27,
     GPGME_STATUS_NEED_PASSPHRASE_SYM = 28,
     GPGME_STATUS_DECRYPTION_FAILED = 29,
     GPGME_STATUS_DECRYPTION_OKAY = 30,
     GPGME_STATUS_MISSING_PASSPHRASE = 31,
     GPGME_STATUS_GOOD_PASSPHRASE = 32,
     GPGME_STATUS_GOODMDC = 33,
     GPGME_STATUS_BADMDC = 34,
     GPGME_STATUS_ERRMDC = 35,
     GPGME_STATUS_IMPORTED = 36,
     GPGME_STATUS_IMPORT_OK = 37,
     GPGME_STATUS_IMPORT_PROBLEM = 38,
     GPGME_STATUS_IMPORT_RES = 39,
     GPGME_STATUS_FILE_START = 40,
     GPGME_STATUS_FILE_DONE = 41,
     GPGME_STATUS_FILE_ERROR = 42,
 
     GPGME_STATUS_BEGIN_DECRYPTION = 43,
     GPGME_STATUS_END_DECRYPTION = 44,
     GPGME_STATUS_BEGIN_ENCRYPTION = 45,
     GPGME_STATUS_END_ENCRYPTION = 46,
 
     GPGME_STATUS_DELETE_PROBLEM = 47,
     GPGME_STATUS_GET_BOOL = 48,
     GPGME_STATUS_GET_LINE = 49,
     GPGME_STATUS_GET_HIDDEN = 50,
     GPGME_STATUS_GOT_IT = 51,
     GPGME_STATUS_PROGRESS = 52,
     GPGME_STATUS_SIG_CREATED = 53,
     GPGME_STATUS_SESSION_KEY = 54,
     GPGME_STATUS_NOTATION_NAME = 55,
     GPGME_STATUS_NOTATION_DATA = 56,
     GPGME_STATUS_POLICY_URL = 57,
     GPGME_STATUS_BEGIN_STREAM = 58,    /* (legacy) */
     GPGME_STATUS_END_STREAM = 59,      /* (legacy) */
     GPGME_STATUS_KEY_CREATED = 60,
     GPGME_STATUS_USERID_HINT = 61,
     GPGME_STATUS_UNEXPECTED = 62,
     GPGME_STATUS_INV_RECP = 63,
     GPGME_STATUS_NO_RECP = 64,
     GPGME_STATUS_ALREADY_SIGNED = 65,
     GPGME_STATUS_SIGEXPIRED = 66,      /* (legacy) */
     GPGME_STATUS_EXPSIG = 67,
     GPGME_STATUS_EXPKEYSIG = 68,
     GPGME_STATUS_TRUNCATED = 69,
     GPGME_STATUS_ERROR = 70,
     GPGME_STATUS_NEWSIG = 71,
     GPGME_STATUS_REVKEYSIG = 72,
     GPGME_STATUS_SIG_SUBPACKET = 73,
     GPGME_STATUS_NEED_PASSPHRASE_PIN = 74,
     GPGME_STATUS_SC_OP_FAILURE = 75,
     GPGME_STATUS_SC_OP_SUCCESS = 76,
     GPGME_STATUS_CARDCTRL = 77,
     GPGME_STATUS_BACKUP_KEY_CREATED = 78,
     GPGME_STATUS_PKA_TRUST_BAD = 79,
     GPGME_STATUS_PKA_TRUST_GOOD = 80,
     GPGME_STATUS_PLAINTEXT = 81,
     GPGME_STATUS_INV_SGNR = 82,
     GPGME_STATUS_NO_SGNR = 83,
     GPGME_STATUS_SUCCESS = 84,
     GPGME_STATUS_DECRYPTION_INFO = 85,
     GPGME_STATUS_PLAINTEXT_LENGTH = 86,
     GPGME_STATUS_MOUNTPOINT = 87,
     GPGME_STATUS_PINENTRY_LAUNCHED = 88,
     GPGME_STATUS_ATTRIBUTE = 89,
     GPGME_STATUS_BEGIN_SIGNING = 90,
     GPGME_STATUS_KEY_NOT_CREATED = 91,
     GPGME_STATUS_INQUIRE_MAXLEN = 92,
     GPGME_STATUS_FAILURE = 93,
     GPGME_STATUS_KEY_CONSIDERED = 94,
     GPGME_STATUS_TOFU_USER = 95,
     GPGME_STATUS_TOFU_STATS = 96,
     GPGME_STATUS_TOFU_STATS_LONG = 97,
     GPGME_STATUS_NOTATION_FLAGS = 98,
     GPGME_STATUS_DECRYPTION_COMPLIANCE_MODE = 99,
     GPGME_STATUS_VERIFICATION_COMPLIANCE_MODE = 100,
     GPGME_STATUS_CANCELED_BY_USER = 101
   }
 gpgme_status_code_t;
 
 /* The callback type used by the deprecated functions gpgme_op_edit
  * and gpgme_op_card_edit.  */
 typedef gpgme_error_t (*gpgme_edit_cb_t) (void *opaque,
 					  gpgme_status_code_t status,
 					  const char *args, int fd);
 
 gpgme_error_t gpgme_op_edit_start (gpgme_ctx_t ctx, gpgme_key_t key,
 				   gpgme_edit_cb_t fnc, void *fnc_value,
 				   gpgme_data_t out) _GPGME_DEPRECATED(1,7);
 gpgme_error_t gpgme_op_edit       (gpgme_ctx_t ctx, gpgme_key_t key,
 			           gpgme_edit_cb_t fnc, void *fnc_value,
 			           gpgme_data_t out) _GPGME_DEPRECATED(1,7);
 gpgme_error_t gpgme_op_card_edit_start (gpgme_ctx_t ctx, gpgme_key_t key,
 					gpgme_edit_cb_t fnc, void *fnc_value,
 					gpgme_data_t out)
                                         _GPGME_DEPRECATED(1,7);
 gpgme_error_t gpgme_op_card_edit       (gpgme_ctx_t ctx, gpgme_key_t key,
 				        gpgme_edit_cb_t fnc, void *fnc_value,
 				        gpgme_data_t out)
                                         _GPGME_DEPRECATED(1,7);
 
 /* The possible signature stati.  Deprecated, use error value in sig
  * status.  */
 typedef enum
   {
     GPGME_SIG_STAT_NONE  = 0,
     GPGME_SIG_STAT_GOOD  = 1,
     GPGME_SIG_STAT_BAD   = 2,
     GPGME_SIG_STAT_NOKEY = 3,
     GPGME_SIG_STAT_NOSIG = 4,
     GPGME_SIG_STAT_ERROR = 5,
     GPGME_SIG_STAT_DIFF  = 6,
     GPGME_SIG_STAT_GOOD_EXP = 7,
     GPGME_SIG_STAT_GOOD_EXPKEY = 8
   }
 _gpgme_sig_stat_t;
 typedef _gpgme_sig_stat_t gpgme_sig_stat_t _GPGME_DEPRECATED(0,4);
 
 /* The available key and signature attributes.  Deprecated, use the
  * individual result structures instead.  */
 typedef enum
   {
     GPGME_ATTR_KEYID        = 1,
     GPGME_ATTR_FPR          = 2,
     GPGME_ATTR_ALGO         = 3,
     GPGME_ATTR_LEN          = 4,
     GPGME_ATTR_CREATED      = 5,
     GPGME_ATTR_EXPIRE       = 6,
     GPGME_ATTR_OTRUST       = 7,
     GPGME_ATTR_USERID       = 8,
     GPGME_ATTR_NAME         = 9,
     GPGME_ATTR_EMAIL        = 10,
     GPGME_ATTR_COMMENT      = 11,
     GPGME_ATTR_VALIDITY     = 12,
     GPGME_ATTR_LEVEL        = 13,
     GPGME_ATTR_TYPE         = 14,
     GPGME_ATTR_IS_SECRET    = 15,
     GPGME_ATTR_KEY_REVOKED  = 16,
     GPGME_ATTR_KEY_INVALID  = 17,
     GPGME_ATTR_UID_REVOKED  = 18,
     GPGME_ATTR_UID_INVALID  = 19,
     GPGME_ATTR_KEY_CAPS     = 20,
     GPGME_ATTR_CAN_ENCRYPT  = 21,
     GPGME_ATTR_CAN_SIGN     = 22,
     GPGME_ATTR_CAN_CERTIFY  = 23,
     GPGME_ATTR_KEY_EXPIRED  = 24,
     GPGME_ATTR_KEY_DISABLED = 25,
     GPGME_ATTR_SERIAL       = 26,
     GPGME_ATTR_ISSUER       = 27,
     GPGME_ATTR_CHAINID      = 28,
     GPGME_ATTR_SIG_STATUS   = 29,
     GPGME_ATTR_ERRTOK       = 30,
     GPGME_ATTR_SIG_SUMMARY  = 31,
     GPGME_ATTR_SIG_CLASS    = 32
   }
 _gpgme_attr_t;
 typedef _gpgme_attr_t gpgme_attr_t _GPGME_DEPRECATED(0,4);
 
 /* Retrieve the signature status of signature IDX in CTX after a
  * successful verify operation in R_STAT (if non-null).  The creation
  * time stamp of the signature is returned in R_CREATED (if non-null).
  * The function returns a string containing the fingerprint.
  * Deprecated, use verify result directly.  */
 const char *gpgme_get_sig_status (gpgme_ctx_t ctx, int idx,
                                   _gpgme_sig_stat_t *r_stat,
 				  time_t *r_created) _GPGME_DEPRECATED(0,4);
 
 /* Retrieve certain attributes of a signature.  IDX is the index
  * number of the signature after a successful verify operation.  WHAT
  * is an attribute where GPGME_ATTR_EXPIRE is probably the most useful
  * one.  WHATIDX is to be passed as 0 for most attributes . */
 unsigned long gpgme_get_sig_ulong_attr (gpgme_ctx_t c, int idx,
                                         _gpgme_attr_t what, int whatidx)
      _GPGME_DEPRECATED(0,4);
 const char *gpgme_get_sig_string_attr (gpgme_ctx_t c, int idx,
 				       _gpgme_attr_t what, int whatidx)
      _GPGME_DEPRECATED(0,4);
 
 
 /* Get the key used to create signature IDX in CTX and return it in
  * R_KEY.  */
 gpgme_error_t gpgme_get_sig_key (gpgme_ctx_t ctx, int idx, gpgme_key_t *r_key)
      _GPGME_DEPRECATED(0,4);
 
 /* Create a new data buffer which retrieves the data from the callback
  * function READ_CB.  Deprecated, please use gpgme_data_new_from_cbs
  * instead.  */
 gpgme_error_t gpgme_data_new_with_read_cb (gpgme_data_t *r_dh,
 					   int (*read_cb) (void*,char *,
 							   size_t,size_t*),
 					   void *read_cb_value)
      _GPGME_DEPRECATED(0,4);
 
 /* Return the value of the attribute WHAT of KEY, which has to be
  * representable by a string.  IDX specifies the sub key or user ID
  * for attributes related to sub keys or user IDs.  Deprecated, use
  * key structure directly instead. */
 const char *gpgme_key_get_string_attr (gpgme_key_t key, _gpgme_attr_t what,
 				       const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 /* Return the value of the attribute WHAT of KEY, which has to be
  * representable by an unsigned integer.  IDX specifies the sub key or
  * user ID for attributes related to sub keys or user IDs.
  * Deprecated, use key structure directly instead.  */
 unsigned long gpgme_key_get_ulong_attr (gpgme_key_t key, _gpgme_attr_t what,
 					const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 /* Return the value of the attribute WHAT of a signature on user ID
  * UID_IDX in KEY, which has to be representable by a string.  IDX
  * specifies the signature.  Deprecated, use key structure directly
  * instead.  */
 const char *gpgme_key_sig_get_string_attr (gpgme_key_t key, int uid_idx,
 					   _gpgme_attr_t what,
 					   const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 /* Return the value of the attribute WHAT of a signature on user ID
  * UID_IDX in KEY, which has to be representable by an unsigned
  * integer string.  IDX specifies the signature.  Deprecated, use key
  * structure directly instead.  */
 unsigned long gpgme_key_sig_get_ulong_attr (gpgme_key_t key, int uid_idx,
 					    _gpgme_attr_t what,
 					    const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 
 gpgme_error_t gpgme_op_import_ext (gpgme_ctx_t ctx, gpgme_data_t keydata,
 				   int *nr) _GPGME_DEPRECATED(0,4);
 
 /* DO NOT USE.  */
 void gpgme_trust_item_release (gpgme_trust_item_t item) _GPGME_DEPRECATED(0,4);
 
 /* DO NOT USE.  */
 const char *gpgme_trust_item_get_string_attr (gpgme_trust_item_t item,
 					      _gpgme_attr_t what,
 					      const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 /* DO NOT USE.  */
 int gpgme_trust_item_get_int_attr (gpgme_trust_item_t item, _gpgme_attr_t what,
 				   const void *reserved, int idx)
      _GPGME_DEPRECATED(0,4);
 
 /* Compat.
  * This structure shall be considered read-only and an application
  * must not allocate such a structure on its own.  */
 struct _gpgme_op_assuan_result
 {
   /* Deprecated.  Use the second value in a DONE event or the
      synchronous variant gpgme_op_assuan_transact_ext.  */
   gpgme_error_t err _GPGME_DEPRECATED_OUTSIDE_GPGME(1,2);
 };
 typedef struct _gpgme_op_assuan_result *gpgme_assuan_result_t;
 
 
 /* Return the result of the last Assuan command. */
 gpgme_assuan_result_t gpgme_op_assuan_result (gpgme_ctx_t ctx)
   _GPGME_DEPRECATED(1,2);
 
 gpgme_error_t
 gpgme_op_assuan_transact (gpgme_ctx_t ctx,
 			      const char *command,
 			      gpgme_assuan_data_cb_t data_cb,
 			      void *data_cb_value,
 			      gpgme_assuan_inquire_cb_t inq_cb,
 			      void *inq_cb_value,
 			      gpgme_assuan_status_cb_t status_cb,
                           void *status_cb_value) _GPGME_DEPRECATED(1,2);
 
 
 
 typedef gpgme_ctx_t GpgmeCtx _GPGME_DEPRECATED(0,4);
 typedef gpgme_data_t GpgmeData _GPGME_DEPRECATED(0,4);
 typedef gpgme_error_t GpgmeError _GPGME_DEPRECATED(0,4);
 typedef gpgme_data_encoding_t GpgmeDataEncoding _GPGME_DEPRECATED(0,4);
 typedef gpgme_pubkey_algo_t GpgmePubKeyAlgo _GPGME_DEPRECATED(0,4);
 typedef gpgme_hash_algo_t GpgmeHashAlgo _GPGME_DEPRECATED(0,4);
 typedef gpgme_sig_stat_t GpgmeSigStat _GPGME_DEPRECATED(0,4);
 typedef gpgme_sig_mode_t GpgmeSigMode _GPGME_DEPRECATED(0,4);
 typedef gpgme_attr_t GpgmeAttr _GPGME_DEPRECATED(0,4);
 typedef gpgme_validity_t GpgmeValidity _GPGME_DEPRECATED(0,4);
 typedef gpgme_protocol_t GpgmeProtocol _GPGME_DEPRECATED(0,4);
 typedef gpgme_engine_info_t GpgmeEngineInfo _GPGME_DEPRECATED(0,4);
 typedef gpgme_subkey_t GpgmeSubkey _GPGME_DEPRECATED(0,4);
 typedef gpgme_key_sig_t GpgmeKeySig _GPGME_DEPRECATED(0,4);
 typedef gpgme_user_id_t GpgmeUserID _GPGME_DEPRECATED(0,4);
 typedef gpgme_key_t GpgmeKey _GPGME_DEPRECATED(0,4);
 typedef gpgme_passphrase_cb_t GpgmePassphraseCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_progress_cb_t GpgmeProgressCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_io_cb_t GpgmeIOCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_register_io_cb_t GpgmeRegisterIOCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_remove_io_cb_t GpgmeRemoveIOCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_event_io_t GpgmeEventIO _GPGME_DEPRECATED(0,4);
 typedef gpgme_event_io_cb_t GpgmeEventIOCb _GPGME_DEPRECATED(0,4);
 #define GpgmeIOCbs gpgme_io_cbs
 typedef gpgme_data_read_cb_t GpgmeDataReadCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_data_write_cb_t GpgmeDataWriteCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_data_seek_cb_t GpgmeDataSeekCb _GPGME_DEPRECATED(0,4);
 typedef gpgme_data_release_cb_t GpgmeDataReleaseCb _GPGME_DEPRECATED(0,4);
 #define GpgmeDataCbs gpgme_data_cbs
 typedef gpgme_encrypt_result_t GpgmeEncryptResult _GPGME_DEPRECATED(0,4);
 typedef gpgme_sig_notation_t GpgmeSigNotation _GPGME_DEPRECATED(0,4);
 typedef	gpgme_signature_t GpgmeSignature _GPGME_DEPRECATED(0,4);
 typedef gpgme_verify_result_t GpgmeVerifyResult _GPGME_DEPRECATED(0,4);
 typedef gpgme_import_status_t GpgmeImportStatus _GPGME_DEPRECATED(0,4);
 typedef gpgme_import_result_t GpgmeImportResult _GPGME_DEPRECATED(0,4);
 typedef gpgme_genkey_result_t GpgmeGenKeyResult _GPGME_DEPRECATED(0,4);
 typedef	gpgme_trust_item_t GpgmeTrustItem _GPGME_DEPRECATED(0,4);
 typedef gpgme_status_code_t GpgmeStatusCode _GPGME_DEPRECATED(0,4);
 
 #ifdef __cplusplus
 }
 #endif
 #endif /* GPGME_H */
 /*
 @emacs_local_vars_begin@
 @emacs_local_vars_read_only@
 @emacs_local_vars_end@
 */
diff --git a/src/key.c b/src/key.c
index e4b85774..322bd0ac 100644
--- a/src/key.c
+++ b/src/key.c
@@ -1,781 +1,782 @@
 /* key.c - Key objects.
  * Copyright (C) 2000 Werner Koch (dd9jn)
  * Copyright (C) 2001, 2002, 2003, 2004 g10 Code GmbH
  *
  * This file is part of GPGME.
  *
  * GPGME is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * GPGME is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, see <https://gnu.org/licenses/>.
  * SPDX-License-Identifier: LGPL-2.1-or-later
  */
 
 #if HAVE_CONFIG_H
 #include <config.h>
 #endif
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
 #include <errno.h>
 
 #include "util.h"
 #include "ops.h"
 #include "sema.h"
 #include "debug.h"
 #include "mbox-util.h"
 
 
 
 /* Protects all reference counters in keys.  All other accesses to a
    key are read only.  */
 DEFINE_STATIC_LOCK (key_ref_lock);
 
 
 /* Create a new key.  */
 gpgme_error_t
 _gpgme_key_new (gpgme_key_t *r_key)
 {
   gpgme_key_t key;
 
   key = calloc (1, sizeof *key);
   if (!key)
     return gpg_error_from_syserror ();
   key->_refs = 1;
 
   *r_key = key;
   return 0;
 }
 
 
 gpgme_error_t
 _gpgme_key_add_subkey (gpgme_key_t key, gpgme_subkey_t *r_subkey)
 {
   gpgme_subkey_t subkey;
 
   subkey = calloc (1, sizeof *subkey);
   if (!subkey)
     return gpg_error_from_syserror ();
   subkey->keyid = subkey->_keyid;
   subkey->_keyid[16] = '\0';
 
   if (!key->subkeys)
     key->subkeys = subkey;
   if (key->_last_subkey)
     key->_last_subkey->next = subkey;
   key->_last_subkey = subkey;
 
   *r_subkey = subkey;
   return 0;
 }
 
 
 static char *
 set_user_id_part (char *tail, const char *buf, size_t len)
 {
   while (len && (buf[len - 1] == ' ' || buf[len - 1] == '\t'))
     len--;
   for (; len; len--)
     *tail++ = *buf++;
   *tail++ = 0;
   return tail;
 }
 
 
 static void
 parse_user_id (char *src, char **name, char **email,
 	       char **comment, char *tail)
 {
   const char *start = NULL;
   int in_name = 0;
   int in_email = 0;
   int in_comment = 0;
 
   while (*src)
     {
       if (in_email)
 	{
 	  if (*src == '<')
 	    /* Not legal but anyway.  */
 	    in_email++;
 	  else if (*src == '>')
 	    {
 	      if (!--in_email && !*email)
 		{
 		  *email = tail;
 		  tail = set_user_id_part (tail, start, src - start);
 		}
 	    }
 	}
       else if (in_comment)
 	{
 	  if (*src == '(')
 	    in_comment++;
 	  else if (*src == ')')
 	    {
 	      if (!--in_comment && !*comment)
 		{
 		  *comment = tail;
 		  tail = set_user_id_part (tail, start, src - start);
 		}
 	    }
 	}
       else if (*src == '<')
 	{
 	  if (in_name)
 	    {
 	      if (!*name)
 		{
 		  *name = tail;
 		  tail = set_user_id_part (tail, start, src - start);
 		}
 	      in_name = 0;
 	    }
 	  in_email = 1;
 	  start = src + 1;
 	}
       else if (*src == '(')
 	{
 	  if (in_name)
 	    {
 	      if (!*name)
 		{
 		  *name = tail;
 		  tail = set_user_id_part (tail, start, src - start);
 		}
 	      in_name = 0;
 	    }
 	  in_comment = 1;
 	  start = src + 1;
 	}
       else if (!in_name && *src != ' ' && *src != '\t')
 	{
 	  in_name = 1;
 	  start = src;
 	}
       src++;
     }
 
   if (in_name)
     {
       if (!*name)
 	{
 	  *name = tail;
 	  tail = set_user_id_part (tail, start, src - start);
 	}
     }
 
   /* Let unused parts point to an EOS.  */
   tail--;
   if (!*name)
     *name = tail;
   if (!*email)
     *email = tail;
   if (!*comment)
     *comment = tail;
 }
 
 
 static void
 parse_x509_user_id (char *src, char **name, char **email,
 		    char **comment, char *tail)
 {
   if (*src == '<' && src[strlen (src) - 1] == '>')
     *email = src;
 
   /* Let unused parts point to an EOS.  */
   tail--;
   if (!*name)
     *name = tail;
   if (!*email)
     *email = tail;
   if (!*comment)
     *comment = tail;
 }
 
 
 /* Take a name from the --with-colon listing, remove certain escape
    sequences sequences and put it into the list of UIDs.  */
 gpgme_error_t
 _gpgme_key_append_name (gpgme_key_t key, const char *src, int convert)
 {
   gpgme_user_id_t uid;
   char *dst;
   int src_len = strlen (src);
 
   assert (key);
   /* We can malloc a buffer of the same length, because the converted
      string will never be larger. Actually we allocate it twice the
      size, so that we are able to store the parsed stuff there too.  */
   uid = malloc (sizeof (*uid) + 2 * src_len + 3);
   if (!uid)
     return gpg_error_from_syserror ();
   memset (uid, 0, sizeof *uid);
 
   uid->uid = ((char *) uid) + sizeof (*uid);
   dst = uid->uid;
   if (convert)
     _gpgme_decode_c_string (src, &dst, src_len + 1);
   else
     memcpy (dst, src, src_len + 1);
 
   dst += strlen (dst) + 1;
   if (key->protocol == GPGME_PROTOCOL_CMS)
     parse_x509_user_id (uid->uid, &uid->name, &uid->email,
 			&uid->comment, dst);
   else
     parse_user_id (uid->uid, &uid->name, &uid->email,
 		   &uid->comment, dst);
 
   uid->address = _gpgme_mailbox_from_userid (uid->uid);
   if ((!uid->email || !*uid->email) && uid->address && uid->name
       && !strcmp (uid->name, uid->address))
     {
       /* Name and address are the same. This is a mailbox only key.
          Use address as email and remove name. */
       *uid->name = '\0';
       uid->email = uid->address;
     }
 
   if (!key->uids)
     key->uids = uid;
   if (key->_last_uid)
     key->_last_uid->next = uid;
   key->_last_uid = uid;
 
   return 0;
 }
 
 
 gpgme_key_sig_t
 _gpgme_key_add_sig (gpgme_key_t key, char *src)
 {
   int src_len = src ? strlen (src) : 0;
   gpgme_user_id_t uid;
   gpgme_key_sig_t sig;
 
   assert (key);	/* XXX */
 
   uid = key->_last_uid;
   assert (uid);	/* XXX */
 
   /* We can malloc a buffer of the same length, because the converted
      string will never be larger.  Actually we allocate it twice the
      size, so that we are able to store the parsed stuff there too.  */
   sig = malloc (sizeof (*sig) + 2 * src_len + 3);
   if (!sig)
     return NULL;
   memset (sig, 0, sizeof *sig);
 
   sig->keyid = sig->_keyid;
   sig->_keyid[16] = '\0';
   sig->uid = ((char *) sig) + sizeof (*sig);
 
   if (src)
     {
       char *dst = sig->uid;
       _gpgme_decode_c_string (src, &dst, src_len + 1);
       dst += strlen (dst) + 1;
       if (key->protocol == GPGME_PROTOCOL_CMS)
 	parse_x509_user_id (sig->uid, &sig->name, &sig->email,
 			    &sig->comment, dst);
       else
 	parse_user_id (sig->uid, &sig->name, &sig->email,
 		       &sig->comment, dst);
     }
   else
     sig->uid[0] = '\0';
 
   if (!uid->signatures)
     uid->signatures = sig;
   if (uid->_last_keysig)
     uid->_last_keysig->next = sig;
   uid->_last_keysig = sig;
 
   return sig;
 }
 
 
 /* Acquire a reference to KEY.  */
 void
 gpgme_key_ref (gpgme_key_t key)
 {
   LOCK (key_ref_lock);
   key->_refs++;
   UNLOCK (key_ref_lock);
 }
 
 
 /* gpgme_key_unref releases the key object.  Note, that this function
    may not do an actual release if there are other shallow copies of
    the objects.  You have to call this function for every newly
    created key object as well as for every gpgme_key_ref() done on the
    key object.  */
 void
 gpgme_key_unref (gpgme_key_t key)
 {
   gpgme_user_id_t uid;
   gpgme_subkey_t subkey;
 
   if (!key)
     return;
 
   LOCK (key_ref_lock);
   assert (key->_refs > 0);
   if (--key->_refs)
     {
       UNLOCK (key_ref_lock);
       return;
     }
   UNLOCK (key_ref_lock);
 
   subkey = key->subkeys;
   while (subkey)
     {
       gpgme_subkey_t next = subkey->next;
       free (subkey->fpr);
       free (subkey->curve);
       free (subkey->keygrip);
       free (subkey->card_number);
       free (subkey);
       subkey = next;
     }
 
   uid = key->uids;
   while (uid)
     {
       gpgme_user_id_t next_uid = uid->next;
       gpgme_key_sig_t keysig = uid->signatures;
       gpgme_tofu_info_t tofu = uid->tofu;
 
       while (keysig)
 	{
 	  gpgme_key_sig_t next_keysig = keysig->next;
 	  gpgme_sig_notation_t notation = keysig->notations;
 
 	  while (notation)
 	    {
 	      gpgme_sig_notation_t next_notation = notation->next;
 
 	      _gpgme_sig_notation_free (notation);
 	      notation = next_notation;
 	    }
 
+	  free (keysig->trust_scope);
           free (keysig);
 	  keysig = next_keysig;
         }
 
       while (tofu)
         {
           /* NB: The ->next is currently not used but we are prepared
            * for it.  */
           gpgme_tofu_info_t tofu_next = tofu->next;
 
           free (tofu->description);
           free (tofu);
           tofu = tofu_next;
         }
 
       free (uid->address);
       free (uid->uidhash);
       free (uid);
       uid = next_uid;
     }
 
   free (key->issuer_serial);
   free (key->issuer_name);
   free (key->chain_id);
   free (key->fpr);
 
   free (key);
 }
 
 
 
 /* Support functions.  */
 
 /* Create a dummy key to specify an email address.  */
 gpgme_error_t
 gpgme_key_from_uid (gpgme_key_t *r_key, const char *name)
 {
   gpgme_error_t err;
   gpgme_key_t key;
 
   *r_key = NULL;
   err = _gpgme_key_new (&key);
   if (err)
     return err;
 
   /* Note: protocol doesn't matter if only email is provided.  */
   err = _gpgme_key_append_name (key, name, 0);
   if (err)
     gpgme_key_unref (key);
   else
     *r_key = key;
 
   return err;
 }
 
 
 
 /* Compatibility interfaces.  */
 
 void
 gpgme_key_release (gpgme_key_t key)
 {
   gpgme_key_unref (key);
 }
 
 
 static const char *
 otrust_to_string (int otrust)
 {
   switch (otrust)
     {
     case GPGME_VALIDITY_NEVER:
       return "n";
 
     case GPGME_VALIDITY_MARGINAL:
       return "m";
 
     case GPGME_VALIDITY_FULL:
       return "f";
 
     case GPGME_VALIDITY_ULTIMATE:
       return "u";
 
     default:
       return "?";
     }
 }
 
 
 static const char *
 validity_to_string (int validity)
 {
   switch (validity)
     {
     case GPGME_VALIDITY_UNDEFINED:
       return "q";
 
     case GPGME_VALIDITY_NEVER:
       return "n";
 
     case GPGME_VALIDITY_MARGINAL:
       return "m";
 
     case GPGME_VALIDITY_FULL:
       return "f";
 
     case GPGME_VALIDITY_ULTIMATE:
       return "u";
 
     case GPGME_VALIDITY_UNKNOWN:
     default:
       return "?";
     }
 }
 
 
 static const char *
 capabilities_to_string (gpgme_subkey_t subkey)
 {
   static const char *const strings[8] =
     {
       "",
       "c",
       "s",
       "sc",
       "e",
       "ec",
       "es",
       "esc"
     };
   return strings[(!!subkey->can_encrypt << 2)
 		 | (!!subkey->can_sign << 1)
 		 | (!!subkey->can_certify)];
 }
 
 
 /* Return the value of the attribute WHAT of ITEM, which has to be
    representable by a string.  */
 const char *
 gpgme_key_get_string_attr (gpgme_key_t key, _gpgme_attr_t what,
 			   const void *reserved, int idx)
 {
   gpgme_subkey_t subkey;
   gpgme_user_id_t uid;
   int i;
 
   if (!key || reserved || idx < 0)
     return NULL;
 
   /* Select IDXth subkey.  */
   subkey = key->subkeys;
   for (i = 0; i < idx; i++)
     {
       subkey = subkey->next;
       if (!subkey)
 	break;
     }
 
   /* Select the IDXth user ID.  */
   uid = key->uids;
   for (i = 0; i < idx; i++)
     {
       uid = uid->next;
       if (!uid)
 	break;
     }
 
   switch (what)
     {
     case GPGME_ATTR_KEYID:
       return subkey ? subkey->keyid : NULL;
 
     case GPGME_ATTR_FPR:
       return subkey ? subkey->fpr : NULL;
 
     case GPGME_ATTR_ALGO:
       return subkey ? gpgme_pubkey_algo_name (subkey->pubkey_algo) : NULL;
 
     case GPGME_ATTR_TYPE:
       return key->protocol == GPGME_PROTOCOL_CMS ? "X.509" : "PGP";
 
     case GPGME_ATTR_OTRUST:
       return otrust_to_string (key->owner_trust);
 
     case GPGME_ATTR_USERID:
       return uid ? uid->uid : NULL;
 
     case GPGME_ATTR_NAME:
       return uid ? uid->name : NULL;
 
     case GPGME_ATTR_EMAIL:
       return uid ? uid->email : NULL;
 
     case GPGME_ATTR_COMMENT:
       return uid ? uid->comment : NULL;
 
     case GPGME_ATTR_VALIDITY:
       return uid ? validity_to_string (uid->validity) : NULL;
 
     case GPGME_ATTR_KEY_CAPS:
       return subkey ? capabilities_to_string (subkey) : NULL;
 
     case GPGME_ATTR_SERIAL:
       return key->issuer_serial;
 
     case GPGME_ATTR_ISSUER:
       return idx ? NULL : key->issuer_name;
 
     case GPGME_ATTR_CHAINID:
       return key->chain_id;
 
     default:
       return NULL;
     }
 }
 
 
 unsigned long
 gpgme_key_get_ulong_attr (gpgme_key_t key, _gpgme_attr_t what,
 			  const void *reserved, int idx)
 {
   gpgme_subkey_t subkey;
   gpgme_user_id_t uid;
   int i;
 
   if (!key || reserved || idx < 0)
     return 0;
 
   /* Select IDXth subkey.  */
   subkey = key->subkeys;
   for (i = 0; i < idx; i++)
     {
       subkey = subkey->next;
       if (!subkey)
 	break;
     }
 
   /* Select the IDXth user ID.  */
   uid = key->uids;
   for (i = 0; i < idx; i++)
     {
       uid = uid->next;
       if (!uid)
 	break;
     }
 
   switch (what)
     {
     case GPGME_ATTR_ALGO:
       return subkey ? (unsigned long) subkey->pubkey_algo : 0;
 
     case GPGME_ATTR_LEN:
       return subkey ? (unsigned long) subkey->length : 0;
 
     case GPGME_ATTR_TYPE:
       return key->protocol == GPGME_PROTOCOL_CMS ? 1 : 0;
 
     case GPGME_ATTR_CREATED:
       return (subkey && subkey->timestamp >= 0)
 	? (unsigned long) subkey->timestamp : 0;
 
     case GPGME_ATTR_EXPIRE:
       return (subkey && subkey->expires >= 0)
 	? (unsigned long) subkey->expires : 0;
 
     case GPGME_ATTR_VALIDITY:
       return uid ? uid->validity : 0;
 
     case GPGME_ATTR_OTRUST:
       return key->owner_trust;
 
     case GPGME_ATTR_IS_SECRET:
       return !!key->secret;
 
     case GPGME_ATTR_KEY_REVOKED:
       return subkey ? subkey->revoked : 0;
 
     case GPGME_ATTR_KEY_INVALID:
       return subkey ? subkey->invalid : 0;
 
     case GPGME_ATTR_KEY_EXPIRED:
       return subkey ? subkey->expired : 0;
 
     case GPGME_ATTR_KEY_DISABLED:
       return subkey ? subkey->disabled : 0;
 
     case GPGME_ATTR_UID_REVOKED:
       return uid ? uid->revoked : 0;
 
     case GPGME_ATTR_UID_INVALID:
       return uid ? uid->invalid : 0;
 
     case GPGME_ATTR_CAN_ENCRYPT:
       return key->can_encrypt;
 
     case GPGME_ATTR_CAN_SIGN:
       return key->can_sign;
 
     case GPGME_ATTR_CAN_CERTIFY:
       return key->can_certify;
 
     default:
       return 0;
     }
 }
 
 
 static gpgme_key_sig_t
 get_keysig (gpgme_key_t key, int uid_idx, int idx)
 {
   gpgme_user_id_t uid;
   gpgme_key_sig_t sig;
 
   if (!key || uid_idx < 0 || idx < 0)
     return NULL;
 
   uid = key->uids;
   while (uid && uid_idx > 0)
     {
       uid = uid->next;
       uid_idx--;
     }
   if (!uid)
     return NULL;
 
   sig = uid->signatures;
   while (sig && idx > 0)
     {
       sig = sig->next;
       idx--;
     }
   return sig;
 }
 
 
 const char *
 gpgme_key_sig_get_string_attr (gpgme_key_t key, int uid_idx,
 			       _gpgme_attr_t what,
 			       const void *reserved, int idx)
 {
   gpgme_key_sig_t certsig = get_keysig (key, uid_idx, idx);
 
   if (!certsig || reserved)
     return NULL;
 
   switch (what)
     {
     case GPGME_ATTR_KEYID:
       return certsig->keyid;
 
     case GPGME_ATTR_ALGO:
       return gpgme_pubkey_algo_name (certsig->pubkey_algo);
 
     case GPGME_ATTR_USERID:
       return certsig->uid;
 
     case GPGME_ATTR_NAME:
       return certsig->name;
 
     case GPGME_ATTR_EMAIL:
       return certsig->email;
 
     case GPGME_ATTR_COMMENT:
       return certsig->comment;
 
     default:
       return NULL;
     }
 }
 
 
 unsigned long
 gpgme_key_sig_get_ulong_attr (gpgme_key_t key, int uid_idx, _gpgme_attr_t what,
 			      const void *reserved, int idx)
 {
   gpgme_key_sig_t certsig = get_keysig (key, uid_idx, idx);
 
   if (!certsig || reserved)
     return 0;
 
   switch (what)
     {
     case GPGME_ATTR_ALGO:
       return (unsigned long) certsig->pubkey_algo;
 
     case GPGME_ATTR_CREATED:
       return certsig->timestamp < 0 ? 0L : (unsigned long) certsig->timestamp;
 
     case GPGME_ATTR_EXPIRE:
       return certsig->expires < 0 ? 0L : (unsigned long) certsig->expires;
 
     case GPGME_ATTR_KEY_REVOKED:
       return certsig->revoked;
 
     case GPGME_ATTR_KEY_INVALID:
       return certsig->invalid;
 
     case GPGME_ATTR_KEY_EXPIRED:
       return certsig->expired;
 
     case GPGME_ATTR_SIG_CLASS:
       return certsig->sig_class;
 
     case GPGME_ATTR_SIG_STATUS:
       return certsig->status;
 
     default:
       return 0;
     }
 }
diff --git a/src/keylist.c b/src/keylist.c
index a4de3ad5..42743f07 100644
--- a/src/keylist.c
+++ b/src/keylist.c
@@ -1,1351 +1,1375 @@
 /* keylist.c - Listing keys.
  * Copyright (C) 2000 Werner Koch (dd9jn)
  * Copyright (C) 2001, 2002, 2003, 2004, 2006, 2007,
  *               2008, 2009  g10 Code GmbH
  *
  * This file is part of GPGME.
  *
  * GPGME is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * GPGME is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, see <https://gnu.org/licenses/>.
  * SPDX-License-Identifier: LGPL-2.1-or-later
  */
 
 #if HAVE_CONFIG_H
 #include <config.h>
 #endif
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #ifdef HAVE_SYS_TYPES_H
   /* Solaris 8 needs sys/types.h before time.h.  */
 # include <sys/types.h>
 #endif
 #include <time.h>
 #include <assert.h>
 #include <ctype.h>
 #include <errno.h>
 #include <limits.h>
 
 /* Suppress warning for accessing deprecated member "class".  */
 #define _GPGME_IN_GPGME
 #include "gpgme.h"
 #include "util.h"
 #include "context.h"
 #include "ops.h"
 #include "debug.h"
 
 
 struct key_queue_item_s
 {
   struct key_queue_item_s *next;
   gpgme_key_t key;
 };
 
 typedef struct
 {
   struct _gpgme_op_keylist_result result;
 
   /* The error code from ERROR keydb_search. */
   gpgme_error_t keydb_search_err;
 
   gpgme_key_t tmp_key;
 
   /* This points to the last uid in tmp_key.  */
   gpgme_user_id_t tmp_uid;
 
   /* This points to the last sig in tmp_uid.  */
   gpgme_key_sig_t tmp_keysig;
 
   /* Something new is available.  */
   int key_cond;
   struct key_queue_item_s *key_queue;
 } *op_data_t;
 
 
 static void
 release_op_data (void *hook)
 {
   op_data_t opd = (op_data_t) hook;
   struct key_queue_item_s *key = opd->key_queue;
 
   if (opd->tmp_key)
     gpgme_key_unref (opd->tmp_key);
 
   /* opd->tmp_uid and opd->tmp_keysig are actually part of opd->tmp_key,
      so we do not need to release them here.  */
 
   while (key)
     {
       struct key_queue_item_s *next = key->next;
 
       gpgme_key_unref (key->key);
       key = next;
     }
 }
 
 
 gpgme_keylist_result_t
 gpgme_op_keylist_result (gpgme_ctx_t ctx)
 {
   void *hook;
   op_data_t opd;
   gpgme_error_t err;
 
   TRACE_BEG (DEBUG_CTX, "gpgme_op_keylist_result", ctx, "");
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook, -1, NULL);
   opd = hook;
   if (err || !opd)
     {
       TRACE_SUC ("result=(null)");
       return NULL;
     }
 
   TRACE_LOG  ("truncated = %i", opd->result.truncated);
 
   TRACE_SUC ("result=%p", &opd->result);
   return &opd->result;
 }
 
 
 static gpgme_error_t
 keylist_status_handler (void *priv, gpgme_status_code_t code, char *args)
 {
   gpgme_ctx_t ctx = (gpgme_ctx_t) priv;
   gpgme_error_t err;
   void *hook;
   op_data_t opd;
 
   (void)args;
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook, -1, NULL);
   opd = hook;
   if (err)
     return err;
 
   switch (code)
     {
     case GPGME_STATUS_TRUNCATED:
       opd->result.truncated = 1;
       break;
 
     case GPGME_STATUS_ERROR:
       err = _gpgme_parse_failure (args);
       if (!opd->keydb_search_err && !strcmp (args, "keydb_search"))
         opd->keydb_search_err = err;
       err = 0;
       break;
 
     default:
       break;
     }
   return err;
 }
 
 
 static void
 set_subkey_trust_info (gpgme_subkey_t subkey, const char *src)
 {
   while (*src && !isdigit (*src))
     {
       switch (*src)
 	{
 	case 'e':
 	  subkey->expired = 1;
 	  break;
 
 	case 'r':
 	  subkey->revoked = 1;
 	  break;
 
 	case 'd':
           /* Note that gpg 1.3 won't print that anymore but only uses
              the capabilities field. */
 	  subkey->disabled = 1;
 	  break;
 
 	case 'i':
 	  subkey->invalid = 1;
 	  break;
         }
       src++;
     }
 }
 
 
 static void
 set_mainkey_trust_info (gpgme_key_t key, const char *src)
 {
   /* First set the trust info of the main key (the first subkey).  */
   set_subkey_trust_info (key->subkeys, src);
 
   /* Now set the summarized trust info.  */
   while (*src && !isdigit (*src))
     {
       switch (*src)
 	{
 	case 'e':
 	  key->expired = 1;
 	  break;
 
 	case 'r':
 	  key->revoked = 1;
 	  break;
 
 	case 'd':
           /* Note that gpg 1.3 won't print that anymore but only uses
              the capabilities field.  However, it is still used for
              external key listings.  */
 	  key->disabled = 1;
 	  break;
 
 	case 'i':
 	  key->invalid = 1;
 	  break;
         }
       src++;
     }
 }
 
 
 static void
 set_userid_flags (gpgme_key_t key, const char *src)
 {
   gpgme_user_id_t uid = key->_last_uid;
 
   assert (uid);
   /* Look at letters and stop at the first digit.  */
   while (*src && !isdigit (*src))
     {
       switch (*src)
 	{
 	case 'r':
 	  uid->revoked = 1;
 	  break;
 
 	case 'i':
 	  uid->invalid = 1;
 	  break;
 
 	case 'n':
 	  uid->validity = GPGME_VALIDITY_NEVER;
 	  break;
 
 	case 'm':
 	  uid->validity = GPGME_VALIDITY_MARGINAL;
 	  break;
 
 	case 'f':
 	  uid->validity = GPGME_VALIDITY_FULL;
 	  break;
 
 	case 'u':
 	  uid->validity = GPGME_VALIDITY_ULTIMATE;
 	  break;
         }
       src++;
     }
 }
 
 
 static void
 set_subkey_capability (gpgme_subkey_t subkey, const char *src)
 {
   while (*src)
     {
       switch (*src)
 	{
 	case 'e':
 	  subkey->can_encrypt = 1;
 	  break;
 
 	case 's':
 	  subkey->can_sign = 1;
 	  break;
 
 	case 'c':
 	  subkey->can_certify = 1;
 	  break;
 
 	case 'a':
 	  subkey->can_authenticate = 1;
 	  break;
 
 	case 'q':
 	  subkey->is_qualified = 1;
 	  break;
 
 	case 'd':
 	  subkey->disabled = 1;
 	  break;
         }
       src++;
     }
 }
 
 
 static void
 set_mainkey_capability (gpgme_key_t key, const char *src)
 {
   /* First set the capabilities of the main key (the first subkey).  */
   set_subkey_capability (key->subkeys, src);
 
   while (*src)
     {
       switch (*src)
 	{
 	case 'd':
         case 'D':
           /* Note, that this flag is also set using the key validity
              field for backward compatibility with gpg 1.2.  We use d
              and D, so that a future gpg version will be able to
              disable certain subkeys. Currently it is expected that
              gpg sets this for the primary key. */
        	  key->disabled = 1;
           break;
 
 	case 'e':
 	case 'E':
 	  key->can_encrypt = 1;
 	  break;
 
 	case 's':
 	case 'S':
 	  key->can_sign = 1;
 	  break;
 
 	case 'c':
 	case 'C':
 	  key->can_certify = 1;
 	  break;
 
 	case 'a':
 	case 'A':
 	  key->can_authenticate = 1;
 	  break;
 
 	case 'q':
 	case 'Q':
 	  key->is_qualified = 1;
 	  break;
         }
       src++;
     }
 }
 
 
 static void
 set_ownertrust (gpgme_key_t key, const char *src)
 {
   /* Look at letters and stop at the first digit.  */
   while (*src && !isdigit (*src))
     {
       switch (*src)
 	{
 	case 'n':
 	  key->owner_trust = GPGME_VALIDITY_NEVER;
 	  break;
 
 	case 'm':
 	  key->owner_trust = GPGME_VALIDITY_MARGINAL;
 	  break;
 
 	case 'f':
 	  key->owner_trust = GPGME_VALIDITY_FULL;
 	  break;
 
 	case 'u':
 	  key->owner_trust = GPGME_VALIDITY_ULTIMATE;
 	  break;
 
         default:
 	  key->owner_trust = GPGME_VALIDITY_UNKNOWN;
 	  break;
         }
       src++;
     }
 }
 
 
 static gpgme_keyorg_t
 parse_keyorg (const char *string)
 {
   switch (atoi (string))
     {
     case 0: return GPGME_KEYORG_UNKNOWN;
     case 1:
     case 2:
       return GPGME_KEYORG_KS;
     case 3: return GPGME_KEYORG_DANE;
     case 4: return GPGME_KEYORG_WKD;
     case 5: return GPGME_KEYORG_URL;
     case 6: return GPGME_KEYORG_FILE;
     case 7: return GPGME_KEYORG_SELF;
     default: return GPGME_KEYORG_OTHER;
     }
 }
 
 
 /* Parse field 15 of a secret key or subkey.  This fields holds a
    reference to smartcards.  FIELD is the content of the field and we
    are allowed to modify it.  */
 static gpg_error_t
 parse_sec_field15 (gpgme_key_t key, gpgme_subkey_t subkey, char *field)
 {
   if (!*field)
     ; /* Empty.  */
   else if (*field == '#')
     {
       /* This is a stub for an offline key.  We reset the SECRET flag
          of the subkey here.  Note that the secret flag of the entire
          key will be true even then.  We even explicitly set
          key->secret to make it works for GPGME_KEYLIST_MODE_WITH_SECRET. */
       subkey->secret = 0;
       key->secret = 1;
     }
   else if (strchr ("01234567890ABCDEFabcdef", *field))
     {
       /* Fields starts with a hex digit; thus it is a serial number.  */
       key->secret = 1;
       subkey->is_cardkey = 1;
       subkey->card_number = strdup (field);
       if (!subkey->card_number)
         return gpg_error_from_syserror ();
     }
   else if (*field == '+')
     {
       key->secret = 1;
       subkey->secret = 1;
     }
   else
     {
       /* RFU.  */
     }
 
   return 0;
 }
 
 
 /* Parse a tfs record.  */
 static gpg_error_t
 parse_tfs_record (gpgme_user_id_t uid, char **field, int nfield)
 {
   gpg_error_t err;
   gpgme_tofu_info_t ti;
   unsigned long uval;
 
   /* We add only the first TOFU record in case future versions emit
    * several.  */
   if (uid->tofu)
     return 0;
 
   /* Check that we have enough fields and that the version is supported.  */
   if (nfield < 8 || atoi(field[1]) != 1)
     return trace_gpg_error (GPG_ERR_INV_ENGINE);
 
   ti = calloc (1, sizeof *ti);
   if (!ti)
     return gpg_error_from_syserror ();
 
   /* Note that we allow a value of up to 7 which is what we can store
    * in the ti->validity.  */
   err = _gpgme_strtoul_field (field[2], &uval);
   if (err || uval > 7)
     goto inv_engine;
   ti->validity = uval;
 
   /* Parse the sign-count.  */
   err = _gpgme_strtoul_field (field[3], &uval);
   if (err)
     goto inv_engine;
   if (uval > USHRT_MAX)
     uval = USHRT_MAX;
   ti->signcount = uval;
 
   /* Parse the encr-count.  */
   err = _gpgme_strtoul_field (field[4], &uval);
   if (err)
     goto inv_engine;
   if (uval > USHRT_MAX)
     uval = USHRT_MAX;
   ti->encrcount = uval;
 
   /* Parse the policy.  */
   if (!strcmp (field[5], "none"))
     ti->policy = GPGME_TOFU_POLICY_NONE;
   else if (!strcmp (field[5], "auto"))
     ti->policy = GPGME_TOFU_POLICY_AUTO;
   else if (!strcmp (field[5], "good"))
     ti->policy = GPGME_TOFU_POLICY_GOOD;
   else if (!strcmp (field[5], "bad"))
     ti->policy = GPGME_TOFU_POLICY_BAD;
   else if (!strcmp (field[5], "ask"))
     ti->policy = GPGME_TOFU_POLICY_ASK;
   else /* "unknown" and invalid policy strings.  */
     ti->policy = GPGME_TOFU_POLICY_UNKNOWN;
 
   /* Parse first and last seen timestamps.  */
   err = _gpgme_strtoul_field (field[6], &uval);
   if (err)
     goto inv_engine;
   ti->signfirst = uval;
   err = _gpgme_strtoul_field (field[7], &uval);
   if (err)
     goto inv_engine;
   ti->signlast = uval;
 
   if (nfield > 9)
     {
       /* This condition is only to allow for gpg 2.1.15 - can
        * eventually be removed.  */
       err = _gpgme_strtoul_field (field[8], &uval);
       if (err)
         goto inv_engine;
       ti->encrfirst = uval;
       err = _gpgme_strtoul_field (field[9], &uval);
       if (err)
         goto inv_engine;
       ti->encrlast = uval;
     }
 
   /* Ready.  */
   uid->tofu = ti;
   return 0;
 
  inv_engine:
   free (ti);
   return trace_gpg_error (GPG_ERR_INV_ENGINE);
 }
 
 
 /* We have read an entire key into tmp_key and should now finish it.
    It is assumed that this releases tmp_key.  */
 static void
 finish_key (gpgme_ctx_t ctx, op_data_t opd)
 {
   gpgme_key_t key = opd->tmp_key;
 
   opd->tmp_key = NULL;
   opd->tmp_uid = NULL;
   opd->tmp_keysig = NULL;
 
   if (key)
     _gpgme_engine_io_event (ctx->engine, GPGME_EVENT_NEXT_KEY, key);
 }
 
 
 /* Note: We are allowed to modify LINE.  */
 static gpgme_error_t
 keylist_colon_handler (void *priv, char *line)
 {
   gpgme_ctx_t ctx = (gpgme_ctx_t) priv;
   enum
     {
       RT_NONE, RT_SIG, RT_UID, RT_TFS, RT_SUB, RT_PUB, RT_FPR, RT_GRP,
       RT_SSB, RT_SEC, RT_CRT, RT_CRS, RT_REV, RT_SPK
     }
   rectype = RT_NONE;
 #define NR_FIELDS 20
   char *field[NR_FIELDS];
   int fields = 0;
   void *hook;
   op_data_t opd;
   gpgme_error_t err;
   gpgme_key_t key;
   gpgme_subkey_t subkey = NULL;
   gpgme_key_sig_t keysig = NULL;
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook, -1, NULL);
   opd = hook;
   if (err)
     return err;
 
   key = opd->tmp_key;
 
   TRACE (DEBUG_CTX, "gpgme:keylist_colon_handler", ctx,
 	  "key = %p, line = %s", key, line ? line : "(null)");
 
   if (!line)
     {
       /* End Of File.  */
       finish_key (ctx, opd);
       return 0;
     }
 
   while (line && fields < NR_FIELDS)
     {
       field[fields++] = line;
       line = strchr (line, ':');
       if (line)
 	*(line++) = '\0';
     }
 
   if (!strcmp (field[0], "sig"))
     rectype = RT_SIG;
   else if (!strcmp (field[0], "rev"))
     rectype = RT_REV;
   else if (!strcmp (field[0], "pub"))
     rectype = RT_PUB;
   else if (!strcmp (field[0], "sec"))
     rectype = RT_SEC;
   else if (!strcmp (field[0], "crt"))
     rectype = RT_CRT;
   else if (!strcmp (field[0], "crs"))
     rectype = RT_CRS;
   else if (!strcmp (field[0], "fpr") && key)
     rectype = RT_FPR;
   else if (!strcmp (field[0], "grp") && key)
     rectype = RT_GRP;
   else if (!strcmp (field[0], "uid") && key)
     rectype = RT_UID;
   else if (!strcmp (field[0], "tfs") && key)
     rectype = RT_TFS;
   else if (!strcmp (field[0], "sub") && key)
     rectype = RT_SUB;
   else if (!strcmp (field[0], "ssb") && key)
     rectype = RT_SSB;
   else if (!strcmp (field[0], "spk") && key)
     rectype = RT_SPK;
   else
     rectype = RT_NONE;
 
   /* Only look at signature and trust info records immediately
      following a user ID.  For this, clear the user ID pointer when
      encountering anything but a signature, trust record or subpacket.  */
   if (rectype != RT_SIG && rectype != RT_REV && rectype != RT_TFS &&
       rectype != RT_SPK)
     opd->tmp_uid = NULL;
 
   /* Only look at subpackets immediately following a signature.  For
      this, clear the signature pointer when encountering anything but
      a subpacket.  */
   if (rectype != RT_SPK)
     opd->tmp_keysig = NULL;
 
   switch (rectype)
     {
     case RT_PUB:
     case RT_SEC:
     case RT_CRT:
     case RT_CRS:
       /* Start a new keyblock.  */
       err = _gpgme_key_new (&key);
       if (err)
 	return err;
       key->keylist_mode = ctx->keylist_mode;
       err = _gpgme_key_add_subkey (key, &subkey);
       if (err)
 	{
 	  gpgme_key_unref (key);
 	  return err;
 	}
 
       if (rectype == RT_SEC || rectype == RT_CRS)
 	key->secret = subkey->secret = 1;
       if (rectype == RT_CRT || rectype == RT_CRS)
 	key->protocol = GPGME_PROTOCOL_CMS;
       finish_key (ctx, opd);
       opd->tmp_key = key;
 
       /* Field 2 has the trust info.  */
       if (fields >= 2)
 	set_mainkey_trust_info (key, field[1]);
 
       /* Field 3 has the key length.  */
       if (fields >= 3)
 	{
 	  int i = atoi (field[2]);
 	  /* Ignore invalid values.  */
 	  if (i > 1)
 	    subkey->length = i;
 	}
 
       /* Field 4 has the public key algorithm.  */
       if (fields >= 4)
 	{
 	  int i = atoi (field[3]);
 	  if (i >= 1 && i < 128)
 	    subkey->pubkey_algo = _gpgme_map_pk_algo (i, ctx->protocol);
 	}
 
       /* Field 5 has the long keyid.  Allow short key IDs for the
 	 output of an external keyserver listing.  */
       if (fields >= 5 && strlen (field[4]) <= DIM(subkey->_keyid) - 1)
 	strcpy (subkey->_keyid, field[4]);
 
       /* Field 6 has the timestamp (seconds).  */
       if (fields >= 6)
 	subkey->timestamp = _gpgme_parse_timestamp (field[5], NULL);
 
       /* Field 7 has the expiration time (seconds).  */
       if (fields >= 7)
 	subkey->expires = _gpgme_parse_timestamp (field[6], NULL);
 
       /* Field 8 has the X.509 serial number.  */
       if (fields >= 8 && (rectype == RT_CRT || rectype == RT_CRS))
 	{
 	  key->issuer_serial = strdup (field[7]);
 	  if (!key->issuer_serial)
 	    return gpg_error_from_syserror ();
 	}
 
       /* Field 9 has the ownertrust.  */
       if (fields >= 9)
 	set_ownertrust (key, field[8]);
 
       /* Field 10 is not used for gpg due to --fixed-list-mode option
 	 but GPGSM stores the issuer name.  */
       if (fields >= 10 && (rectype == RT_CRT || rectype == RT_CRS))
 	if (_gpgme_decode_c_string (field[9], &key->issuer_name, 0))
 	  return gpg_error (GPG_ERR_ENOMEM);	/* FIXME */
 
       /* Field 11 has the signature class.  */
 
       /* Field 12 has the capabilities.  */
       if (fields >= 12)
 	set_mainkey_capability (key, field[11]);
 
       /* Field 15 carries special flags of a secret key.  */
       if (fields >= 15
           && (key->secret
               || (ctx->keylist_mode & GPGME_KEYLIST_MODE_WITH_SECRET)))
         {
           err = parse_sec_field15 (key, subkey, field[14]);
           if (err)
             return err;
         }
 
       /* Field 17 has the curve name for ECC.  */
       if (fields >= 17 && *field[16])
         {
           subkey->curve = strdup (field[16]);
           if (!subkey->curve)
             return gpg_error_from_syserror ();
         }
 
       /* Field 18 has the compliance flags.  */
       if (fields >= 17 && *field[17])
         PARSE_COMPLIANCE_FLAGS (field[17], subkey);
 
       if (fields >= 20)
         {
           key->last_update = _gpgme_parse_timestamp_ul (field[18]);
           key->origin = parse_keyorg (field[19]);
         }
 
       break;
 
     case RT_SUB:
     case RT_SSB:
       /* Start a new subkey.  */
       err = _gpgme_key_add_subkey (key, &subkey);
       if (err)
 	return err;
 
       if (rectype == RT_SSB)
 	subkey->secret = 1;
 
       /* Field 2 has the trust info.  */
       if (fields >= 2)
 	set_subkey_trust_info (subkey, field[1]);
 
       /* Field 3 has the key length.  */
       if (fields >= 3)
 	{
 	  int i = atoi (field[2]);
 	  /* Ignore invalid values.  */
 	  if (i > 1)
 	    subkey->length = i;
 	}
 
       /* Field 4 has the public key algorithm.  */
       if (fields >= 4)
 	{
 	  int i = atoi (field[3]);
 	  if (i >= 1 && i < 128)
 	    subkey->pubkey_algo = _gpgme_map_pk_algo (i, ctx->protocol);
 	}
 
       /* Field 5 has the long keyid.  */
       if (fields >= 5 && strlen (field[4]) == DIM(subkey->_keyid) - 1)
 	strcpy (subkey->_keyid, field[4]);
 
       /* Field 6 has the timestamp (seconds).  */
       if (fields >= 6)
 	subkey->timestamp = _gpgme_parse_timestamp (field[5], NULL);
 
       /* Field 7 has the expiration time (seconds).  */
       if (fields >= 7)
 	subkey->expires = _gpgme_parse_timestamp (field[6], NULL);
 
       /* Field 8 is reserved (LID).  */
       /* Field 9 has the ownertrust.  */
       /* Field 10, the user ID, is n/a for a subkey.  */
 
       /* Field 11 has the signature class.  */
 
       /* Field 12 has the capabilities.  */
       if (fields >= 12)
 	set_subkey_capability (subkey, field[11]);
 
       /* Field 15 carries special flags of a secret key. */
       if (fields >= 15
           && (key->secret
               || (ctx->keylist_mode & GPGME_KEYLIST_MODE_WITH_SECRET)))
         {
           err = parse_sec_field15 (key, subkey, field[14]);
           if (err)
             return err;
         }
 
       /* Field 17 has the curve name for ECC.  */
       if (fields >= 17 && *field[16])
         {
           subkey->curve = strdup (field[16]);
           if (!subkey->curve)
             return gpg_error_from_syserror ();
         }
 
       /* Field 18 has the compliance flags.  */
       if (fields >= 17 && *field[17])
         PARSE_COMPLIANCE_FLAGS (field[17], subkey);
 
       break;
 
     case RT_UID:
       /* Field 2 has the trust info, and field 10 has the user ID.  */
       if (fields >= 10)
 	{
 	  if (_gpgme_key_append_name (key, field[9], 1))
 	    return gpg_error (GPG_ERR_ENOMEM);	/* FIXME */
 
           if (field[1])
             set_userid_flags (key, field[1]);
           if (field[7] && *field[7])
             {
               gpgme_user_id_t uid = key->_last_uid;
               assert (uid);
               uid->uidhash = strdup (field[7]);
             }
           opd->tmp_uid = key->_last_uid;
           if (fields >= 20)
             {
               opd->tmp_uid->last_update = _gpgme_parse_timestamp_ul (field[18]);
               opd->tmp_uid->origin = parse_keyorg (field[19]);
             }
 	}
       break;
 
     case RT_TFS:
       if (opd->tmp_uid)
 	{
           err = parse_tfs_record (opd->tmp_uid, field, fields);
           if (err)
             return err;
         }
       break;
 
     case RT_FPR:
       /* Field 10 has the fingerprint (take only the first one).  */
       if (fields >= 10 && field[9] && *field[9])
 	{
           /* Need to apply it to the last subkey because all subkeys
              do have fingerprints. */
           subkey = key->_last_subkey;
           if (!subkey->fpr)
             {
               subkey->fpr = strdup (field[9]);
               if (!subkey->fpr)
                 return gpg_error_from_syserror ();
             }
           /* If this is the first subkey, store the fingerprint also
              in the KEY object.  */
           if (subkey == key->subkeys)
             {
               if (key->fpr && strcmp (key->fpr, subkey->fpr))
                 {
                   /* FPR already set but mismatch: Should never happen.  */
                   return trace_gpg_error (GPG_ERR_INTERNAL);
                 }
               if (!key->fpr)
                 {
                   key->fpr = strdup (subkey->fpr);
                   if (!key->fpr)
                     return gpg_error_from_syserror ();
                 }
             }
 	}
 
       /* Field 13 has the gpgsm chain ID (take only the first one).  */
       if (fields >= 13 && !key->chain_id && *field[12])
 	{
 	  key->chain_id = strdup (field[12]);
 	  if (!key->chain_id)
 	    return gpg_error_from_syserror ();
 	}
       break;
 
     case RT_GRP:
       /* Field 10 has the keygrip.  */
       if (fields >= 10 && field[9] && *field[9])
 	{
           /* Need to apply it to the last subkey because all subkeys
              have a keygrip. */
           subkey = key->_last_subkey;
           if (!subkey->keygrip)
             {
               subkey->keygrip = strdup (field[9]);
               if (!subkey->keygrip)
                 return gpg_error_from_syserror ();
             }
 	}
       break;
 
     case RT_SIG:
     case RT_REV:
       if (!opd->tmp_uid)
 	return 0;
 
       /* Start a new (revoked) signature.  */
       assert (opd->tmp_uid == key->_last_uid);
       keysig = _gpgme_key_add_sig (key, (fields >= 10) ? field[9] : NULL);
       if (!keysig)
 	return gpg_error (GPG_ERR_ENOMEM);	/* FIXME */
 
       /* Field 2 has the calculated trust ('!', '-', '?', '%').  */
       if (fields >= 2)
 	switch (field[1][0])
 	  {
 	  case '!':
 	    keysig->status = gpg_error (GPG_ERR_NO_ERROR);
 	    break;
 
 	  case '-':
 	    keysig->status = gpg_error (GPG_ERR_BAD_SIGNATURE);
 	    break;
 
 	  case '?':
 	    keysig->status = gpg_error (GPG_ERR_NO_PUBKEY);
 	    break;
 
 	  case '%':
 	    keysig->status = gpg_error (GPG_ERR_GENERAL);
 	    break;
 
 	  default:
 	    keysig->status = gpg_error (GPG_ERR_NO_ERROR);
 	    break;
 	  }
 
       /* Field 4 has the public key algorithm.  */
       if (fields >= 4)
 	{
 	  int i = atoi (field[3]);
 	  if (i >= 1 && i < 128)
 	    keysig->pubkey_algo = _gpgme_map_pk_algo (i, ctx->protocol);
 	}
 
       /* Field 5 has the long keyid.  */
       if (fields >= 5 && strlen (field[4]) == DIM(keysig->_keyid) - 1)
 	strcpy (keysig->_keyid, field[4]);
 
       /* Field 6 has the timestamp (seconds).  */
       if (fields >= 6)
 	keysig->timestamp = _gpgme_parse_timestamp (field[5], NULL);
 
       /* Field 7 has the expiration time (seconds).  */
       if (fields >= 7)
 	keysig->expires = _gpgme_parse_timestamp (field[6], NULL);
 
+      /* Field 8 has the trust depth and the trust value.  */
+      if (fields >= 8 && *field[7])
+        {
+          const char *trust_depth = field[7];
+          char *trust_value = strchr (field[7] + 1, ' ');
+          if (trust_value)
+            *(trust_value++) = '\0';
+          if (trust_value)
+            {
+              int depth = atoi (trust_depth);
+              int value = atoi (trust_value);
+
+              if (depth >= 1 && depth < 256)
+                keysig->trust_depth = depth;
+              if (value >= 1 && value < 256)
+                keysig->trust_value = value;
+            }
+        }
+
+      /* Field 9 has the trust signature scope (a regular expression).  */
+      if (fields >= 9)
+	if (_gpgme_decode_c_string (field[8], &keysig->trust_scope, 0))
+	  return gpg_error (GPG_ERR_ENOMEM);	/* FIXME */
+
       /* Field 11 has the signature class (eg, 0x30 means revoked).  */
       if (fields >= 11)
 	if (field[10][0] && field[10][1])
 	  {
 	    int sig_class = _gpgme_hextobyte (field[10]);
 	    if (sig_class >= 0)
 	      {
 		keysig->sig_class = sig_class;
 		keysig->class = keysig->sig_class;
 		if (sig_class == 0x30)
 		  keysig->revoked = 1;
 	      }
 	    if (field[10][2] == 'x')
 	      keysig->exportable = 1;
 	  }
 
       opd->tmp_keysig = keysig;
       break;
 
     case RT_SPK:
       if (!opd->tmp_keysig)
 	return 0;
       assert (opd->tmp_keysig == key->_last_uid->_last_keysig);
 
       if (fields >= 4)
 	{
 	  /* Field 2 has the subpacket type.  */
 	  int type = atoi (field[1]);
 
 	  /* Field 3 has the flags.  */
 	  int flags = atoi (field[2]);
 
 	  /* Field 4 has the length.  */
 	  int len = atoi (field[3]);
 
 	  /* Field 5 has the data.  */
 	  char *data = field[4];
 
 	  /* Type 20: Notation data.  */
 	  /* Type 26: Policy URL.  */
 	  if (type == 20 || type == 26)
 	    {
 	      gpgme_sig_notation_t notation;
 
 	      keysig = opd->tmp_keysig;
 
 	      /* At this time, any error is serious.  */
 	      err = _gpgme_parse_notation (&notation, type, flags, len, data);
 	      if (err)
 		return err;
 
 	      /* Add a new notation.  FIXME: Could be factored out.  */
 	      if (!keysig->notations)
 		keysig->notations = notation;
 	      if (keysig->_last_notation)
 		keysig->_last_notation->next = notation;
 	      keysig->_last_notation = notation;
 	    }
 	}
 
     case RT_NONE:
       /* Unknown record.  */
       break;
     }
   return 0;
 }
 
 
 void
 _gpgme_op_keylist_event_cb (void *data, gpgme_event_io_t type, void *type_data)
 {
   gpgme_error_t err;
   gpgme_ctx_t ctx = (gpgme_ctx_t) data;
   gpgme_key_t key = (gpgme_key_t) type_data;
   void *hook;
   op_data_t opd;
   struct key_queue_item_s *q, *q2;
 
   assert (type == GPGME_EVENT_NEXT_KEY);
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook, -1, NULL);
   opd = hook;
   if (err)
     return;
 
   q = malloc (sizeof *q);
   if (!q)
     {
       gpgme_key_unref (key);
       /* FIXME       return GPGME_Out_Of_Core; */
       return;
     }
   q->key = key;
   q->next = NULL;
   /* FIXME: Use a tail pointer?  */
   if (!(q2 = opd->key_queue))
     opd->key_queue = q;
   else
     {
       for (; q2->next; q2 = q2->next)
 	;
       q2->next = q;
     }
   opd->key_cond = 1;
 }
 
 
 /* Start a keylist operation within CTX, searching for keys which
    match PATTERN.  If SECRET_ONLY is true, only secret keys are
    returned.  */
 gpgme_error_t
 gpgme_op_keylist_start (gpgme_ctx_t ctx, const char *pattern, int secret_only)
 {
   gpgme_error_t err;
   void *hook;
   op_data_t opd;
   int flags = 0;
 
   TRACE_BEG  (DEBUG_CTX, "gpgme_op_keylist_start", ctx,
 	      "pattern=%s, secret_only=%i", pattern, secret_only);
 
   if (!ctx)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   err = _gpgme_op_reset (ctx, 2);
   if (err)
     return TRACE_ERR (err);
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook,
 			       sizeof (*opd), release_op_data);
   opd = hook;
   if (err)
     return TRACE_ERR (err);
 
   _gpgme_engine_set_status_handler (ctx->engine, keylist_status_handler, ctx);
 
   err = _gpgme_engine_set_colon_line_handler (ctx->engine,
 					      keylist_colon_handler, ctx);
   if (err)
     return TRACE_ERR (err);
 
   if (ctx->offline)
     flags |= GPGME_ENGINE_FLAG_OFFLINE;
 
   err = _gpgme_engine_op_keylist (ctx->engine, pattern, secret_only,
 				  ctx->keylist_mode, flags);
   return TRACE_ERR (err);
 }
 
 
 /* Start a keylist operation within CTX, searching for keys which
    match PATTERN.  If SECRET_ONLY is true, only secret keys are
    returned.  */
 gpgme_error_t
 gpgme_op_keylist_ext_start (gpgme_ctx_t ctx, const char *pattern[],
 			    int secret_only, int reserved)
 {
   gpgme_error_t err;
   void *hook;
   op_data_t opd;
   int flags = 0;
 
   TRACE_BEG  (DEBUG_CTX, "gpgme_op_keylist_ext_start", ctx,
 	      "secret_only=%i, reserved=0x%x", secret_only, reserved);
 
   if (!ctx)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   err = _gpgme_op_reset (ctx, 2);
   if (err)
     return TRACE_ERR (err);
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook,
 			       sizeof (*opd), release_op_data);
   opd = hook;
   if (err)
     return TRACE_ERR (err);
 
   _gpgme_engine_set_status_handler (ctx->engine, keylist_status_handler, ctx);
   err = _gpgme_engine_set_colon_line_handler (ctx->engine,
 					      keylist_colon_handler, ctx);
   if (err)
     return TRACE_ERR (err);
 
   if (ctx->offline)
     flags |= GPGME_ENGINE_FLAG_OFFLINE;
 
   err = _gpgme_engine_op_keylist_ext (ctx->engine, pattern, secret_only,
 				      reserved, ctx->keylist_mode,
 				      flags);
   return TRACE_ERR (err);
 }
 
 
 /* Start a keylist operation within CTX to show keys contained
  * in DATA.  */
 gpgme_error_t
 gpgme_op_keylist_from_data_start (gpgme_ctx_t ctx, gpgme_data_t data,
                                   int reserved)
 {
   gpgme_error_t err;
   void *hook;
   op_data_t opd;
 
   TRACE_BEG (DEBUG_CTX, "gpgme_op_keylist_from_data_start", ctx, "");
 
   if (!ctx || !data || reserved)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   err = _gpgme_op_reset (ctx, 2);
   if (err)
     return TRACE_ERR (err);
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook,
                                sizeof (*opd), release_op_data);
   opd = hook;
   if (err)
     return TRACE_ERR (err);
 
   _gpgme_engine_set_status_handler (ctx->engine, keylist_status_handler, ctx);
   err = _gpgme_engine_set_colon_line_handler (ctx->engine,
                                               keylist_colon_handler, ctx);
   if (err)
     return TRACE_ERR (err);
 
   err = _gpgme_engine_op_keylist_data (ctx->engine, data);
   return TRACE_ERR (err);
 }
 
 
 /* Return the next key from the keylist in R_KEY.  */
 gpgme_error_t
 gpgme_op_keylist_next (gpgme_ctx_t ctx, gpgme_key_t *r_key)
 {
   gpgme_error_t err;
   struct key_queue_item_s *queue_item;
   void *hook;
   op_data_t opd;
 
   TRACE_BEG (DEBUG_CTX, "gpgme_op_keylist_next", ctx, "");
 
   if (!ctx || !r_key)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
   *r_key = NULL;
   if (!ctx)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   err = _gpgme_op_data_lookup (ctx, OPDATA_KEYLIST, &hook, -1, NULL);
   opd = hook;
   if (err)
     return TRACE_ERR (err);
   if (opd == NULL)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   if (!opd->key_queue)
     {
       err = _gpgme_wait_on_condition (ctx, &opd->key_cond, NULL);
       if (err)
 	return TRACE_ERR (err);
 
       if (!opd->key_cond)
 	return TRACE_ERR (opd->keydb_search_err? opd->keydb_search_err
                           /**/                 : gpg_error (GPG_ERR_EOF));
 
       opd->key_cond = 0;
       assert (opd->key_queue);
     }
   queue_item = opd->key_queue;
   opd->key_queue = queue_item->next;
   if (!opd->key_queue)
     opd->key_cond = 0;
 
   *r_key = queue_item->key;
   free (queue_item);
 
   TRACE_SUC ("key=%p (%s)", *r_key,
              ((*r_key)->subkeys && (*r_key)->subkeys->fpr) ?
              (*r_key)->subkeys->fpr : "invalid");
   return 0;
 }
 
 
 /* Terminate a pending keylist operation within CTX.  */
 gpgme_error_t
 gpgme_op_keylist_end (gpgme_ctx_t ctx)
 {
   TRACE (DEBUG_CTX, "gpgme_op_keylist_end", ctx, "");
 
   if (!ctx)
     return gpg_error (GPG_ERR_INV_VALUE);
 
   return 0;
 }
 
 
 /* Get the key with the fingerprint FPR from the crypto backend.  If
    SECRET is true, get the secret key.  */
 gpgme_error_t
 gpgme_get_key (gpgme_ctx_t ctx, const char *fpr, gpgme_key_t *r_key,
 	       int secret)
 {
   gpgme_ctx_t listctx;
   gpgme_error_t err;
   gpgme_key_t result, key;
 
   TRACE_BEG  (DEBUG_CTX, "gpgme_get_key", ctx,
 	      "fpr=%s, secret=%i", fpr, secret);
 
   if (r_key)
     *r_key = NULL;
 
   if (!ctx || !r_key || !fpr)
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   if (strlen (fpr) < 8)	/* We have at least a key ID.  */
     return TRACE_ERR (gpg_error (GPG_ERR_INV_VALUE));
 
   /* FIXME: We use our own context because we have to avoid the user's
      I/O callback handlers.  */
   err = gpgme_new (&listctx);
   if (err)
     return TRACE_ERR (err);
   {
     gpgme_protocol_t proto;
     gpgme_engine_info_t info;
 
     /* Clone the relevant state.  */
     proto = gpgme_get_protocol (ctx);
     gpgme_set_protocol (listctx, proto);
     gpgme_set_keylist_mode (listctx, gpgme_get_keylist_mode (ctx));
     info = gpgme_ctx_get_engine_info (ctx);
     while (info && info->protocol != proto)
       info = info->next;
     if (info)
       gpgme_ctx_set_engine_info (listctx, proto,
 				 info->file_name, info->home_dir);
   }
 
   err = gpgme_op_keylist_start (listctx, fpr, secret);
   if (!err)
     err = gpgme_op_keylist_next (listctx, &result);
   if (!err)
     {
     try_next_key:
       err = gpgme_op_keylist_next (listctx, &key);
       if (gpgme_err_code (err) == GPG_ERR_EOF)
 	err = 0;
       else
 	{
           if (!err
               && result && result->subkeys && result->subkeys->fpr
               && key && key->subkeys && key->subkeys->fpr
               && !strcmp (result->subkeys->fpr, key->subkeys->fpr))
             {
               /* The fingerprint is identical.  We assume that this is
                  the same key and don't mark it as an ambiguous.  This
                  problem may occur with corrupted keyrings and has
                  been noticed often with gpgsm.  In fact gpgsm uses a
                  similar hack to sort out such duplicates but it can't
                  do that while listing keys.  */
               gpgme_key_unref (key);
               goto try_next_key;
             }
 	  if (!err)
 	    {
 	      gpgme_key_unref (key);
 	      err = gpg_error (GPG_ERR_AMBIGUOUS_NAME);
 	    }
 	  gpgme_key_unref (result);
           result = NULL;
 	}
     }
   gpgme_release (listctx);
   if (! err)
     {
       *r_key = result;
       TRACE_LOG  ("key=%p (%s)", *r_key,
 		  ((*r_key)->subkeys && (*r_key)->subkeys->fpr) ?
 		  (*r_key)->subkeys->fpr : "invalid");
     }
   return TRACE_ERR (err);
 }
diff --git a/tests/run-keylist.c b/tests/run-keylist.c
index 23c61108..f0ab74e8 100644
--- a/tests/run-keylist.c
+++ b/tests/run-keylist.c
@@ -1,427 +1,430 @@
 /* run-keylist.c  - Helper to show a key listing.
  * Copyright (C) 2008, 2009 g10 Code GmbH
  *
  * This file is part of GPGME.
  *
  * GPGME is free software; you can redistribute it and/or modify it
  * under the terms of the GNU Lesser General Public License as
  * published by the Free Software Foundation; either version 2.1 of
  * the License, or (at your option) any later version.
  *
  * GPGME is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with this program; if not, see <https://gnu.org/licenses/>.
  * SPDX-License-Identifier: LGPL-2.1-or-later
  */
 
 /* We need to include config.h so that we know whether we are building
    with large file system (LFS) support. */
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
 
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <time.h>
 
 #include <gpgme.h>
 
 #define PGM "run-keylist"
 
 #include "run-support.h"
 
 
 static int verbose;
 
 
 static int
 show_usage (int ex)
 {
   fputs ("usage: " PGM " [options] [USERID_or_FILE]\n\n"
          "Options:\n"
          "  --verbose        run in verbose mode\n"
          "  --openpgp        use the OpenPGP protocol (default)\n"
          "  --cms            use the CMS protocol\n"
          "  --secret         list only secret keys\n"
          "  --with-secret    list pubkeys with secret info filled\n"
          "  --local          use GPGME_KEYLIST_MODE_LOCAL\n"
          "  --extern         use GPGME_KEYLIST_MODE_EXTERN\n"
          "  --sigs           use GPGME_KEYLIST_MODE_SIGS\n"
          "  --tofu           use GPGME_KEYLIST_MODE_TOFU\n"
          "  --sig-notations  use GPGME_KEYLIST_MODE_SIG_NOTATIONS\n"
          "  --ephemeral      use GPGME_KEYLIST_MODE_EPHEMERAL\n"
          "  --validate       use GPGME_KEYLIST_MODE_VALIDATE\n"
          "  --import         import all keys\n"
          "  --offline        use offline mode\n"
          "  --from-file      list all keys in the given file\n"
          "  --from-wkd       list key from a web key directory\n"
          "  --require-gnupg  required at least the given GnuPG version\n"
          "  --trust-model    use the specified trust-model\n"
          , stderr);
   exit (ex);
 }
 
 
 static const char *
 isotimestr (unsigned long value)
 {
   time_t t;
   static char buffer[25+5];
   struct tm *tp;
 
   if (!value)
     return "none";
   t = value;
 
   tp = gmtime (&t);
   snprintf (buffer, sizeof buffer, "%04d-%02d-%02d %02d:%02d:%02d",
             1900+tp->tm_year, tp->tm_mon+1, tp->tm_mday,
             tp->tm_hour, tp->tm_min, tp->tm_sec);
   return buffer;
 }
 
 
 
 int
 main (int argc, char **argv)
 {
   int last_argc = -1;
   gpgme_error_t err;
   gpgme_ctx_t ctx;
   gpgme_keylist_mode_t mode = 0;
   gpgme_key_t key;
   gpgme_subkey_t subkey;
   gpgme_keylist_result_t result;
   int import = 0;
   gpgme_key_t keyarray[100];
   int keyidx = 0;
   gpgme_protocol_t protocol = GPGME_PROTOCOL_OpenPGP;
   int only_secret = 0;
   int offline = 0;
   int from_file = 0;
   int from_wkd = 0;
   gpgme_data_t data = NULL;
   char *trust_model = NULL;
 
 
   if (argc)
     { argc--; argv++; }
 
   while (argc && last_argc != argc )
     {
       last_argc = argc;
       if (!strcmp (*argv, "--"))
         {
           argc--; argv++;
           break;
         }
       else if (!strcmp (*argv, "--help"))
         show_usage (0);
       else if (!strcmp (*argv, "--verbose"))
         {
           verbose = 1;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--openpgp"))
         {
           protocol = GPGME_PROTOCOL_OpenPGP;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--cms"))
         {
           protocol = GPGME_PROTOCOL_CMS;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--secret"))
         {
           only_secret = 1;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--local"))
         {
           mode |= GPGME_KEYLIST_MODE_LOCAL;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--extern"))
         {
           mode |= GPGME_KEYLIST_MODE_EXTERN;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--tofu"))
         {
           mode |= GPGME_KEYLIST_MODE_WITH_TOFU;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--sigs"))
         {
           mode |= GPGME_KEYLIST_MODE_SIGS;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--sig-notations"))
         {
           mode |= GPGME_KEYLIST_MODE_SIG_NOTATIONS;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--ephemeral"))
         {
           mode |= GPGME_KEYLIST_MODE_EPHEMERAL;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--validate"))
         {
           mode |= GPGME_KEYLIST_MODE_VALIDATE;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--with-secret"))
         {
           mode |= GPGME_KEYLIST_MODE_WITH_SECRET;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--import"))
         {
           import = 1;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--offline"))
         {
           offline = 1;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--from-file"))
         {
           from_file = 1;
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--require-gnupg"))
         {
           argc--; argv++;
           if (!argc)
             show_usage (1);
           gpgme_set_global_flag ("require-gnupg", *argv);
           argc--; argv++;
         }
       else if (!strcmp (*argv, "--from-wkd"))
         {
           argc--; argv++;
           mode |= GPGME_KEYLIST_MODE_LOCATE;
           from_wkd = 1;
         }
       else if (!strcmp (*argv, "--trust-model"))
         {
           argc--; argv++;
           if (!argc)
             show_usage (1);
           trust_model = strdup (*argv);
           argc--; argv++;
         }
       else if (!strncmp (*argv, "--", 2))
         show_usage (1);
     }
 
   if (argc > 1)
     show_usage (1);
   else if (from_file && !argc)
     show_usage (1);
 
   init_gpgme (protocol);
 
   err = gpgme_new (&ctx);
   fail_if_err (err);
   gpgme_set_protocol (ctx, protocol);
 
   gpgme_set_keylist_mode (ctx, mode);
 
   gpgme_set_offline (ctx, offline);
 
   if (trust_model)
     {
       err = gpgme_set_ctx_flag (ctx, "trust-model", trust_model);
       fail_if_err (err);
     }
 
   if (from_wkd)
     {
       err = gpgme_set_ctx_flag (ctx, "auto-key-locate",
                                 "clear,nodefault,wkd");
       fail_if_err (err);
     }
 
   if (from_file)
     {
       err = gpgme_data_new_from_file (&data, *argv, 1);
       fail_if_err (err);
 
       err = gpgme_op_keylist_from_data_start (ctx, data, 0);
     }
   else
     err = gpgme_op_keylist_start (ctx, argc? argv[0]:NULL, only_secret);
   fail_if_err (err);
 
   while (!(err = gpgme_op_keylist_next (ctx, &key)))
     {
       gpgme_user_id_t uid;
       gpgme_tofu_info_t ti;
       gpgme_key_sig_t ks;
       int nuids;
       int nsub;
       int nsigs;
 
       printf ("keyid   : %s\n", key->subkeys?nonnull (key->subkeys->keyid):"?");
       printf ("fpr     : %s\n", key->subkeys?nonnull (key->subkeys->fpr):"?");
       if (key->subkeys && key->subkeys->keygrip)
         printf ("grip    : %s\n", key->subkeys->keygrip);
       if (key->subkeys && key->subkeys->curve)
             printf ("curve   : %s\n", key->subkeys->curve);
       printf ("caps    : %s%s%s%s\n",
               key->can_encrypt? "e":"",
               key->can_sign? "s":"",
               key->can_certify? "c":"",
               key->can_authenticate? "a":"");
       printf ("flags   :%s%s%s%s%s%s%s%s\n",
               key->secret? " secret":"",
               key->revoked? " revoked":"",
               key->expired? " expired":"",
               key->disabled? " disabled":"",
               key->invalid? " invalid":"",
               key->is_qualified? " qualified":"",
               key->subkeys && key->subkeys->is_de_vs? " de-vs":"",
               key->subkeys && key->subkeys->is_cardkey? " cardkey":"");
       printf ("upd     : %lu (%u)\n", key->last_update, key->origin);
 
       subkey = key->subkeys;
       if (subkey)
         subkey = subkey->next;
       for (nsub=1; subkey; subkey = subkey->next, nsub++)
         {
           printf ("fpr   %2d: %s\n", nsub, nonnull (subkey->fpr));
           if (subkey->keygrip)
             printf ("grip  %2d: %s\n", nsub, subkey->keygrip);
           if (subkey->curve)
             printf ("curve %2d: %s\n", nsub, subkey->curve);
           printf ("caps  %2d: %s%s%s%s\n",
                   nsub,
                   subkey->can_encrypt? "e":"",
                   subkey->can_sign? "s":"",
                   subkey->can_certify? "c":"",
                   subkey->can_authenticate? "a":"");
           printf ("flags %2d:%s%s%s%s%s%s%s%s\n",
                   nsub,
                   subkey->secret? " secret":"",
                   subkey->revoked? " revoked":"",
                   subkey->expired? " expired":"",
                   subkey->disabled? " disabled":"",
                   subkey->invalid? " invalid":"",
                   subkey->is_qualified? " qualified":"",
                   subkey->is_de_vs? " de-vs":"",
                   subkey->is_cardkey? " cardkey":"");
         }
       for (nuids=0, uid=key->uids; uid; uid = uid->next, nuids++)
         {
           printf ("userid %d: %s\n", nuids, nonnull(uid->uid));
           printf ("    mbox: %s\n", nonnull(uid->address));
           if (uid->email && uid->email != uid->address)
             printf ("   email: %s\n", uid->email);
           if (uid->name)
             printf ("    name: %s\n", uid->name);
           if (uid->comment)
             printf ("   cmmnt: %s\n", uid->comment);
           if (uid->uidhash)
             printf (" uidhash: %s\n", uid->uidhash);
           printf ("     upd: %lu (%u)\n", uid->last_update, uid->origin);
           printf ("   valid: %s\n",
                   uid->validity == GPGME_VALIDITY_UNKNOWN? "unknown":
                   uid->validity == GPGME_VALIDITY_UNDEFINED? "undefined":
                   uid->validity == GPGME_VALIDITY_NEVER? "never":
                   uid->validity == GPGME_VALIDITY_MARGINAL? "marginal":
                   uid->validity == GPGME_VALIDITY_FULL? "full":
                   uid->validity == GPGME_VALIDITY_ULTIMATE? "ultimate": "[?]");
           if ((ti = uid->tofu))
             {
               printf ("    tofu: %u (%s)\n", ti->validity,
                       ti->validity == 0? "conflict" :
                       ti->validity == 1? "no history" :
                       ti->validity == 2? "little history" :
                       ti->validity == 3? "enough history" :
                       ti->validity == 4? "lot of history" : "?");
               printf ("  policy: %u (%s)\n", ti->policy,
                       ti->policy == GPGME_TOFU_POLICY_NONE? "none" :
                       ti->policy == GPGME_TOFU_POLICY_AUTO? "auto" :
                       ti->policy == GPGME_TOFU_POLICY_GOOD? "good" :
                       ti->policy == GPGME_TOFU_POLICY_UNKNOWN? "unknown" :
                       ti->policy == GPGME_TOFU_POLICY_BAD? "bad" :
                       ti->policy == GPGME_TOFU_POLICY_ASK? "ask" : "?");
               printf ("   nsigs: %hu\n", ti->signcount);
               printf ("   first: %s\n", isotimestr (ti->signfirst));
               printf ("    last: %s\n", isotimestr (ti->signlast));
               printf ("   nencr: %hu\n", ti->encrcount);
               printf ("   first: %s\n", isotimestr (ti->encrfirst));
               printf ("    last: %s\n", isotimestr (ti->encrlast));
             }
           for (nsigs=0, ks=uid->signatures; ks; ks = ks->next, nsigs++)
             {
               printf ("signature %d: %s\n", nsigs, nonnull (ks->uid));
               printf ("       keyid: %s\n", nonnull (ks->keyid));
               printf ("     created: %s\n", isotimestr(ks->timestamp));
               printf ("     expires: %s\n", isotimestr(ks->expires));
               printf ("       class: %x\n", ks->sig_class);
+              printf (" trust depth: %u\n", ks->trust_depth);
+              printf (" trust value: %u\n", ks->trust_value);
+              printf (" trust scope: %s\n", nonnull (ks->trust_scope));
             }
         }
 
       putchar ('\n');
 
       if (import)
         {
           if (keyidx < DIM (keyarray)-1)
             keyarray[keyidx++] = key;
           else
             {
               fprintf (stderr, PGM": too many keys in import mode"
                        "- skipping this key\n");
               gpgme_key_unref (key);
             }
         }
       else
         gpgme_key_unref (key);
     }
   if (gpgme_err_code (err) != GPG_ERR_EOF)
     fail_if_err (err);
   err = gpgme_op_keylist_end (ctx);
   fail_if_err (err);
   keyarray[keyidx] = NULL;
   gpgme_data_release (data);
 
   result = gpgme_op_keylist_result (ctx);
   if (result->truncated)
     {
       fprintf (stderr, PGM ": key listing unexpectedly truncated\n");
       exit (1);
     }
 
   if (import)
     {
       gpgme_import_result_t impres;
 
       err = gpgme_op_import_keys (ctx, keyarray);
       fail_if_err (err);
       impres = gpgme_op_import_result (ctx);
       if (!impres)
         {
           fprintf (stderr, PGM ": no import result returned\n");
           exit (1);
         }
       print_import_result (impres);
     }
 
   for (keyidx=0; keyarray[keyidx]; keyidx++)
     gpgme_key_unref (keyarray[keyidx]);
 
   free (trust_model);
 
   gpgme_release (ctx);
   return 0;
 }