Subject: Re: [PATCH] mingw: avoid fallback for {local,gm}time_r()

From: Junio C Hamano <[email-masked]>
Date: Thu, 25 Nov 2021 22:28:20 -0800

"Carlo Marcelo Arenas Belón via GitGitGadget"
<[email-masked]> writes:

> From: =?UTF-8?q?Carlo=20Marcelo=20Arenas=20Bel=C3=B3n?= <[email-masked]>
>
> mingw-w64's pthread_unistd.h had a bug that mistakenly (because there is
> no support for the *lockfile() functions required[1]) defined
> _POSIX_THREAD_SAFE_FUNCTIONS and that was being worked around since
> 3ecd153a3b (compat/mingw: support MSys2-based MinGW build, 2016-01-14).
>
> the bug was fixed in winphtreads, but as a sideeffect, leaves the

s/the/The/; s/sideeffect/side effect/;

> reentrant functions from time.h not longer visible and therefore breaks

s/not longer/no longer/

> the build.
>
> since the intention all along was to avoid using the fallback functions,

s/since/Since/;

> formalize the use of POSIX by setting the corresponding feature flag and
> to make the intention clearer compile out the fallback functions.

I cannot parse the last sentence.  I am guessing "... make the
intention clearer by compiling out..." or "... make the intention
clearer to compile out...", but I cannot quite tell.

> diff --git a/compat/mingw.c b/compat/mingw.c
> index 9e0cd1e097f..e14f2d5f77c 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1083,6 +1083,7 @@ int pipe(int filedes[2])
>  	return 0;
>  }
>  
> +#ifndef __MINGW64__
>  struct tm *gmtime_r(const time_t *timep, struct tm *result)
>  {
>  	if (gmtime_s(result, timep) == 0)
> @@ -1096,6 +1097,7 @@ struct tm *localtime_r(const time_t *timep, struct tm *result)
>  		return result;
>  	return NULL;
>  }
> +#endif
>  
>  char *mingw_getcwd(char *pointer, int len)
>  {
> diff --git a/git-compat-util.h b/git-compat-util.h
> index d70ce142861..c8005db3fb6 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -127,7 +127,9 @@
>  /* Approximation of the length of the decimal representation of this type. */
>  #define decimal_length(x)	((int)(sizeof(x) * 2.56 + 0.5) + 1)
>  
> -#if defined(__sun__)
> +#ifdef __MINGW64__
> +#define _POSIX_C_SOURCE 1
> +#elif defined(__sun__)
>   /*
>    * On Solaris, when _XOPEN_EXTENDED is set, its header file
>    * forces the programs to be XPG4v2, defeating any _XOPEN_SOURCE
>
> base-commit: cd3e606211bb1cf8bc57f7d76bab98cc17a150bc