libgpg-error-1.61 t-printf error on armhf
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	ametzler1
	Wed, Jun 24, 6:38 PM

Description

Hello,
t-printf fails on armhf with:
t-printf: format "%.100Lf" with LDBL_MAX unexpectly did not fail
FAIL: t-printf

Git bisect pointed to f7ded3ce666ca8e27226dfa05b1e6b8636728441 as offending commit.

Details

Version: 1.61

Revisions and Commits

rE libgpg-error
	rEbfdf7b0b7b62 tests: Skip a test when !HAVE_LONG_DOUBLE_WIDER.

Related Objects

Mentioned Here: rEf7ded3ce666c: Fix possible stack overflow in es_printf for %.100f format.

Event Timeline

ametzler1 created this task.Wed, Jun 24, 6:38 PM

In https://en.cppreference.com/c/language/arithmetic_types#Real_floating_types , it says

long double — extended precision floating-point type. Matches IEEE-754 binary128 format if supported, otherwise matches IEEE-754 binary64-extended format if supported, otherwise matches some non-IEEE-754 extended floating-point format as long as its precision is better than binary64 and range is at least as good as binary64, otherwise matches IEEE-754 binary64 format.
   * binary128 format is used by some HP-UX, SPARC, MIPS, ARM64, and z/OS implementations.
   * The most well known IEEE-754 binary64-extended format is 80-bit x87 extended precision format. It is used by many x86 and x86-64 implementations (a notable exception is MSVC, which implements long double in the same format as double, i.e. binary64).

So, it (long double type, and the value LDBL_MAX) can be IEEE-754 binary64 (the same format as double), with the value of 1.7976931348623157e+308.
This value can be represented with the internal buffer size of libgpg-error implementation.
I don't know about exact limit of armhf, but for the portability, the test need to be fixed.

Here is the fix:

diff --git a/configure.ac b/configure.ac
index e9abe0d..7871769 100644
--- a/configure.ac
+++ b/configure.ac
@@ -276,6 +276,7 @@ AC_C_CONST
 AC_CHECK_SIZEOF(int)
 AC_CHECK_SIZEOF(long)
 AC_CHECK_SIZEOF(long long)
+AC_TYPE_LONG_DOUBLE_WIDER
 
 GNUPG_FUNC_MKDIR_TAKES_ONE_ARG
 
diff --git a/tests/t-printf.c b/tests/t-printf.c
index 6cbd03f..b0a3f3f 100644
--- a/tests/t-printf.c
+++ b/tests/t-printf.c
@@ -449,7 +449,7 @@ check_large_float (void)
             errno, strerror (errno));
     }
   else if (verbose)
-    show ("format \"%%.100f\" with DBL_MAX: ->%s<-\n", buf2);
+    show ("format \"%%.101f\" with DBL_MAX: ->%s<-\n", buf2);
 
   if (strcmp (buf, buf2))
     fail ("format \"%%.100f\" does not match \"%%.101f\"\n" );
@@ -469,6 +469,7 @@ check_large_float (void)
     show ("format \"%%.100Lf\" with DBL_MAX: ->%s<-\n", buf);
   gpgrt_free (buf);
 
+# ifdef HAVE_LONG_DOUBLE_WIDER
   ld = LDBL_MAX;
   buf = gpgrt_bsprintf ("%.100Lf\n", ld);
   if (buf)
@@ -478,6 +479,10 @@ check_large_float (void)
   else if (verbose)
     show ("format \"%%.100Lf\" with LDBL_MAX failed as expected\n");
   gpgrt_free (buf);
+# else
+  if (verbose)
+    show ("LDBL_MAX == DBL_MAX - skipping LDBL_MAX test\n");
+# endif
 
 #endif /*HAVE_LONG_DOUBLE*/
 }

I haven't tested on the particular architecture yet. Only tested on machines with HAVE_LONG_DOUBLE_WIDER.

I found the AC_TYPE_LONG_DOUBLE_WIDER check in rsync.

I confirmed this build on armhf: https://buildd.debian.org/status/fetch.php?pkg=rsync&arch=armhf&ver=3.4.4%2Bds1-1&stamp=1780897385&raw=0
checking for long double with more range or precision than double... no

So, I'm going to commit the change above.

• gniibe added a commit: rEbfdf7b0b7b62: tests: Skip a test when !HAVE_LONG_DOUBLE_WIDER..Thu, Jun 25, 3:59 AM

Thank you, works for me, too.

• gniibe changed the task status from Open to Testing.Fri, Jun 26, 6:40 AM