Change Details

For the FIPS service indicator API, considering the use cases with threads, a variable storing a context is required. It is true that we could overload (== extend) the use of `errno` for that, but it is not cleaner solution. While libgcrypt tries to support builds with C90 compilers on non-modern OSes too, it would be OK to use C compilers' feature of `__thread` specifier for thread-local storage. (For C11/C23, we can use `<threads.h>` and `thread_local`.

For the FIPS service indicator API, considering the use cases with threads, a variable storing a context is required. It is true that we could overload (== extend) the use of `errno` for that, but it is not cleaner solution. While libgcrypt tries to support builds with C90 compilers on non-modern OSes too, it would be OK to use C compilers' feature of `__thread` specifier for thread-local storage. (For C11/C23, we can use `<threads.h>` and `thread_local`.) If it's OK, let us start with `__thread` assuming C compiler support.

For the FIPS service indicator API, considering the use cases with threads, a variable storing a context is required. It is true that we could overload (== extend) the use of `errno` for that, but it is not cleaner solution. While libgcrypt tries to support builds with C90 compilers on non-modern OSes too, it would be OK to use C compilers' feature of `__thread` specifier for thread-local storage. (For C11/C23, we can use `<threads.h>` and `thread_local`.) If it's OK, let us start with `__thread` assuming C compiler support.