Posix?

Thorsten Haude yoo at vranx.de
Sun Jan 13 19:06:37 CET 2008


Hi,

* Bert Wesarg wrote (2008-01-13 19:01):
>On Jan 13, 2008 6:00 PM, Thorsten Haude <yoo at vranx.de> wrote:
>> is there a Posix way to get the environment's Posix level? The things
>> I found seem to only work with glibc.
>What is the GLibc way?

From /usr/include/features.h:

- - - Schnipp - - -
/* These are defined by the user (or the compiler)
   to specify the desired environment:

   __STRICT_ANSI__	ISO Standard C.
   _ISOC99_SOURCE	Extensions to ISO C89 from ISO C99.
   _POSIX_SOURCE	IEEE Std 1003.1.
   _POSIX_C_SOURCE	If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
			if >=199309L, add IEEE Std 1003.1b-1993;
			if >=199506L, add IEEE Std 1003.1c-1995
   _XOPEN_SOURCE	Includes POSIX and XPG things.  Set to 500 if
			Single Unix conformance is wanted, to 600 for the
			upcoming sixth revision.
   _XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
   _LARGEFILE_SOURCE	Some more functions for correct standard I/O.
   _LARGEFILE64_SOURCE	Additional functionality from LFS for large files.
   _FILE_OFFSET_BITS=N	Select default filesystem interface.
   _BSD_SOURCE		ISO C, POSIX, and 4.3BSD things.
   _SVID_SOURCE		ISO C, POSIX, and SVID things.
   _GNU_SOURCE		All of the above, plus GNU extensions.
   _REENTRANT		Select additionally reentrant object.
   _THREAD_SAFE		Same as _REENTRANT, often used by other systems.

   The `-ansi' switch to the GNU C compiler defines __STRICT_ANSI__.
   If none of these are defined, the default is to have _SVID_SOURCE,
   _BSD_SOURCE, and _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
   199506L.  If more than one of these are defined, they accumulate.
   For example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE
   together give you ISO C, 1003.1, and 1003.2, but nothing else.

   These are defined by this file and are used by the
   header files to decide what to declare or define:

   __USE_ISOC99		Define ISO C99 things.
   __USE_POSIX		Define IEEE Std 1003.1 things.
   __USE_POSIX2		Define IEEE Std 1003.2 things.
   __USE_POSIX199309	Define IEEE Std 1003.1, and .1b things.
   __USE_POSIX199506	Define IEEE Std 1003.1, .1b, .1c and .1i things.
   __USE_XOPEN		Define XPG things.
   __USE_XOPEN_EXTENDED	Define X/Open Unix things.
   __USE_UNIX98		Define Single Unix V2 things.
   __USE_XOPEN2K        Define XPG6 things.
   __USE_LARGEFILE	Define correct standard I/O things.
   __USE_LARGEFILE64	Define LFS things with separate names.
   __USE_FILE_OFFSET64	Define 64bit interface as default.
   __USE_BSD		Define 4.3BSD things.
   __USE_SVID		Define SVID things.
   __USE_MISC		Define things common to BSD and System V Unix.
   __USE_GNU		Define GNU extensions.
   __USE_REENTRANT	Define reentrant/thread-safe *_r functions.
   __FAVOR_BSD		Favor 4.3BSD things in cases of conflict.

   The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
   defined by this file unconditionally.  `__GNU_LIBRARY__' is provided
   only for compatibility.  All new code should use the other symbols
   to test for features.

   All macros listed above as possibly being defined by this file are
   explicitly undefined if they are not explicitly defined.
   Feature-test macros that are not defined by the user or compiler
   but are implied by the other feature-test macros defined (or by the
   lack of any definitions) are defined by the file.  */
- - - Schnapp - - -


Thorsten                                   Lynnfield Pioneers: Astral Plane
-- 
Getting a thrill out of some stupid quote is a sign of idiocy.
    - turmeric
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