From c688b4196014e0162a1ff11120f6c9516be0c6cb Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 19 Dec 2013 13:32:42 +0000 Subject: Add _DEFAULT_SOURCE feature test macro. This patch adds a feature test macro _DEFAULT_SOURCE to enable the default set of header declarations. The intention is: if _DEFAULT_SOURCE is not used there is no change to the set of __USE_* macros glibc defines; if it's used on its own, and without compiler options such as -std=c99 that define __STRICT_ANSI__, again, there is no change; if it's used together with the macros it approximately (i.e., apart from __USE_POSIX_IMPLICITLY) implies (-D_BSD_SOURCE -D_SVID_SOURCE -D_POSIX_C_SOURCE=200809L), again, there is no change. Otherwise, it causes the relevant features to be enabled, even if __STRICT_ANSI__, or another feature test macro, would cause them to be disabled. This macro deliberately bundles the POSIX.1-2008 (non-X/Open) functionality with the BSD/SVID/"misc" functionality, rather than defining a macro that gives just the latter, as many of the header cleanups resulting from removing _BSD_SOURCE and _SVID_SOURCE support are only possible when BSD/SVID/"misc" is always bundled with POSIX.1-2008. Tested x86_64. * include/features.h: Update comment documenting feature test macros. Mention _DEFAULT_SOURCE in comment. [_GNU_SOURCE] (_DEFAULT_SOURCE): Undefine and redefine. [_DEFAULT_SOURCE]: Undefine and redefine _DEFAULT_SOURCE, _BSD_SOURCE and _SVID_SOURCE. [!__STRICT_ANSI__ && !_ISOC99_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE && !_XOPEN_SOURCE && !_BSD_SOURCE && !_SVID_SOURCE]: Likewise. [_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE] (__USE_POSIX_IMPLICITLY): Define. [_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE] (_POSIX_SOURCE): Undefine and redefine. [_DEFAULT_SOURCE && !_POSIX_SOURCE && !_POSIX_C_SOURCE] (_POSIX_C_SOURCE): Likewise. * manual/creature.texi (_DEFAULT_SOURCE): Document. (Feature Test Macros): Update documentation of default features. --- include/features.h | 49 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 36 insertions(+), 13 deletions(-) (limited to 'include/features.h') diff --git a/include/features.h b/include/features.h index cff8bfcf8e..6acd5c899d 100644 --- a/include/features.h +++ b/include/features.h @@ -41,17 +41,21 @@ _SVID_SOURCE ISO C, POSIX, and SVID things. _ATFILE_SOURCE Additional *at interfaces. _GNU_SOURCE All of the above, plus GNU extensions. + _DEFAULT_SOURCE The default set of features (taking precedence over + __STRICT_ANSI__). _REENTRANT Select additionally reentrant object. _THREAD_SAFE Same as _REENTRANT, often used by other systems. _FORTIFY_SOURCE If set to numeric value > 0 additional security measures are defined, according to level. - 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 - 200112L. 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. + The `-ansi' switch to the GNU C compiler, and standards conformance + options such as `-std=c99', define __STRICT_ANSI__. If none of + these are defined, or if _DEFAULT_SOURCE is defined, the default is + to have _SVID_SOURCE, _BSD_SOURCE, and _POSIX_SOURCE set to one and + _POSIX_C_SOURCE set to 200809L. 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: @@ -160,6 +164,8 @@ # define _XOPEN_SOURCE_EXTENDED 1 # undef _LARGEFILE64_SOURCE # define _LARGEFILE64_SOURCE 1 +# undef _DEFAULT_SOURCE +# define _DEFAULT_SOURCE 1 # undef _BSD_SOURCE # define _BSD_SOURCE 1 # undef _SVID_SOURCE @@ -168,12 +174,19 @@ # define _ATFILE_SOURCE 1 #endif -/* If nothing (other than _GNU_SOURCE) is defined, - define _BSD_SOURCE and _SVID_SOURCE. */ -#if (!defined __STRICT_ANSI__ && !defined _ISOC99_SOURCE && \ - !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE && \ - !defined _XOPEN_SOURCE && !defined _BSD_SOURCE && !defined _SVID_SOURCE) +/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined, + define _DEFAULT_SOURCE, _BSD_SOURCE and _SVID_SOURCE. */ +#if (defined _DEFAULT_SOURCE \ + || (!defined __STRICT_ANSI__ \ + && !defined _ISOC99_SOURCE \ + && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \ + && !defined _XOPEN_SOURCE \ + && !defined _BSD_SOURCE && !defined _SVID_SOURCE)) +# undef _DEFAULT_SOURCE +# define _DEFAULT_SOURCE 1 +# undef _BSD_SOURCE # define _BSD_SOURCE 1 +# undef _SVID_SOURCE # define _SVID_SOURCE 1 #endif @@ -204,8 +217,18 @@ # define __USE_ISOCXX11 1 #endif -/* If none of the ANSI/POSIX macros are defined, use POSIX.1 and POSIX.2 - (and IEEE Std 1003.1b-1993 unless _XOPEN_SOURCE is defined). */ +/* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE + is defined, use POSIX.1-2008 (or another version depending on + _XOPEN_SOURCE). */ +#ifdef _DEFAULT_SOURCE +# if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE +# define __USE_POSIX_IMPLICITLY 1 +# endif +# undef _POSIX_SOURCE +# define _POSIX_SOURCE 1 +# undef _POSIX_C_SOURCE +# define _POSIX_C_SOURCE 200809L +#endif #if ((!defined __STRICT_ANSI__ || (_XOPEN_SOURCE - 0) >= 500) && \ !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE) # define _POSIX_SOURCE 1 -- cgit v1.2.1