[FFmpeg-devel] [PATCH][RFC] -std=c99
Tue Aug 12 22:47:54 CEST 2008
On Tue, Aug 12, 2008 at 08:56:12PM +0100, M?ns Rullg?rd wrote:
> Michael Niedermayer <michaelni at gmx.at> writes:
> > Hi
> > the patch below adds -std=c99 to the cflags when supported.
> > The advanatges this has is that the compiler uses C99 semantics,
> > that several non C99 features and declarations become disabled by default
> > and thus cannot so easily be used mistakely.
> > Compilation and regression tests pass for me.
> > -fasm is needed for
> > asm()
> > -D_BSD_SOURCE is needed for
> > strncasecmp()
> > inet_aton()
> > gethostname()
> > fd_set()
> > FD_ZERO
> > FD_SET
> > FD_ISSET
> > -D_POSIX_C_SOURCE is needed for:
> > getaddrinfo()
> > gai_strerror()
> > freeaddrinfo()
> > AI_PASSIVE
> > getnameinfo()
> > -D_POSIX_C_SOURCE=2 is needed for:
> > optind
> > optarg
> > getopt()
> > The defines are likely needed for more than what i have listed above,
> > these where just amongth the first that showed up without the specfic option
> Something like this has been on my low-priority TODO list (i.e. things
> that I'd like to do, but probably never will) for some time.
> _POSIX_C_SOURCE and _XOPEN_SOURCE are standard feature selection
> macros, so using those is preferred over the glibc-specific ones.
> Setting _BSD_SOURCE is slightly dangerous, since it makes glibc
> replace a few standard functions with BSD-compatible functions of the
> same name.
according to the actual headers
/* If _BSD_SOURCE was defined by the user, favor BSD over POSIX. */
#if defined _BSD_SOURCE && \
!(defined _POSIX_SOURCE || defined _POSIX_C_SOURCE || \
defined _XOPEN_SOURCE || defined _XOPEN_SOURCE_EXTENDED || \
defined _GNU_SOURCE || defined _SVID_SOURCE)
# define __FAVOR_BSD 1
so because we did define _POSIX_C_SOURCE bsd would not be favored
as far as i can see, i ve not checked the docs as i dont trust them
> Most (all?) of the above-mentioned functions are POSIX standard, so
> there should be no need for _BSD_SOURCE. If anything does require
> this, we should look for a POSIX alternative.
Ill try again with xopen and posix and without bsd
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Everything should be made as simple as possible, but not simpler.
-- Albert Einstein
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