From: Bagas Sanjaya <bagasdotme@gmail.com>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>,
git@vger.kernel.org,
Fabrice Fontaine <fontaine.fabrice@gmail.com>
Subject: Re: [PATCH] git-compat-util: avoid redefining system function names
Date: Sat, 3 Dec 2022 15:02:05 +0700 [thread overview]
Message-ID: <Y4sCfRdWAzjqw7cq@debian.me> (raw)
In-Reply-To: <Y4ncAhIqHkckMljb@coredump.intra.peff.net>
On Fri, Dec 02, 2022 at 06:05:38AM -0500, Jeff King wrote:
> -- >8 --
> Subject: [PATCH] git-compat-util: undefine system names before redeclaring
> them
>
> When we define a macro to point a system function (e.g., flockfile) to
> our custom wrapper, we should make sure that the system did not already
> define it as a macro. This is rarely a problem, but can cause
> compilation failures if both of these are true:
>
> - we decide to define our own wrapper even though the system provides
> the function; we know this happens at least with uclibc, which may
> declare flockfile, etc, without _POSIX_THREAD_SAFE_FUNCTIONS
>
> - the system version is declared as a macro; we know this happens at
> least with uclibc's version of getc_unlocked()
>
> So just handling getc_unlocked() would be sufficient to deal with the
> real-world case we've seen. But since it's easy to do, we may as well be
> defensive about the other macro wrappers added in the previous patch.
>
> Signed-off-by: Jeff King <peff@peff.net>
> ---
> There may be other similar cases lurking throughout the code base, but I
> don't think it's worth anybody's time to go looking for them. If one of
> them triggers on a real platform, we can deal with it then.
>
> git-compat-util.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/git-compat-util.h b/git-compat-util.h
> index 83ec7b7941..76e4b11131 100644
> --- a/git-compat-util.h
> +++ b/git-compat-util.h
> @@ -346,6 +346,7 @@ static inline int git_setitimer(int which UNUSED,
> struct itimerval *newvalue UNUSED) {
> return 0; /* pretend success */
> }
> +#undef setitimer
> #define setitimer(which,value,ovalue) git_setitimer(which,value,ovalue)
> #endif
>
> @@ -1480,6 +1481,9 @@ static inline void git_funlockfile(FILE *fh UNUSED)
> {
> ; /* nothing */
> }
> +#undef flockfile
> +#undef funlockfile
> +#undef getc_unlocked
> #define flockfile(fh) git_flockfile(fh)
> #define funlockfile(fh) git_funlockfile(fh)
> #define getc_unlocked(fh) getc(fh)
The warnings gone away, thanks!
For this patch and the previous one [1],
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
[1]: https://lore.kernel.org/git/Y4fH4rhcSztHwKvK@coredump.intra.peff.net/
--
An old man doll... just what I always wanted! - Clara
next prev parent reply other threads:[~2022-12-03 8:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-25 9:23 [PATCH] git-compat-util.h: Fix build without threads Bagas Sanjaya
2022-11-25 23:47 ` Ævar Arnfjörð Bjarmason
2022-11-28 5:04 ` Jeff King
2022-11-29 3:30 ` Bagas Sanjaya
2022-11-29 3:46 ` Bagas Sanjaya
2022-11-28 5:01 ` Jeff King
2022-11-30 21:15 ` [PATCH] git-compat-util: avoid redefining system function names Jeff King
2022-12-02 10:05 ` Bagas Sanjaya
2022-12-02 11:05 ` Jeff King
2022-12-03 8:02 ` Bagas Sanjaya [this message]
2022-12-07 8:33 ` Bagas Sanjaya
2022-12-07 13:00 ` Jeff King
2022-12-02 11:31 ` Ævar Arnfjörð Bjarmason
2022-12-02 22:50 ` Jeff King
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