[thirdparty/glibc.git] / include / features.h

/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef	_FEATURES_H
#define	_FEATURES_H	1

/* 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.
   _ISOC11_SOURCE	Extensions to ISO C99 from ISO C11.
   __STDC_WANT_LIB_EXT2__
			Extensions to ISO C99 from TR 27431-2:2010.
   __STDC_WANT_IEC_60559_BFP_EXT__
			Extensions to ISO C11 from TS 18661-1:2014.
   __STDC_WANT_IEC_60559_FUNCS_EXT__
			Extensions to ISO C11 from TS 18661-4:2015.
   __STDC_WANT_IEC_60559_TYPES_EXT__
			Extensions to ISO C11 from TS 18661-3:2015.

   _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;
			if >=200112L, all of IEEE 1003.1-2004
			if >=200809L, all of IEEE 1003.1-2008
   _XOPEN_SOURCE	Includes POSIX and XPG things.  Set to 500 if
			Single Unix conformance is wanted, to 600 for the
			sixth revision, to 700 for the seventh 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.
   _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__).

   _FORTIFY_SOURCE	Add security hardening to many library functions.
			Set to 1 or 2; 2 performs stricter checks than 1.

   _REENTRANT, _THREAD_SAFE
			Obsolete; equivalent to _POSIX_C_SOURCE=199506L.

   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 _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
   200809L, as well as enabling miscellaneous functions from BSD and
   SVID.  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:

   __GLIBC_USE (F)	Define things from feature set F.  This is defined
			to 1 or 0; the subsequent macros are either defined
			or undefined, and those tests should be moved to
			__GLIBC_USE.
   __USE_ISOC11		Define ISO C11 things.
   __USE_ISOC99		Define ISO C99 things.
   __USE_ISOC95		Define ISO C90 AMD1 (C95) things.
   __USE_ISOCXX11	Define ISO C++11 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_XOPEN2KXSI     Define XPG6 XSI things.
   __USE_XOPEN2K8       Define XPG7 things.
   __USE_XOPEN2K8XSI    Define XPG7 XSI 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_MISC		Define things from 4.3BSD or System V Unix.
   __USE_ATFILE		Define *at interfaces and AT_* constants for them.
   __USE_GNU		Define GNU extensions.
   __USE_FORTIFY_LEVEL	Additional security measures used, according to level.

   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.

   ISO C feature test macros depend on the definition of the macro
   when an affected header is included, not when the first system
   header is included, and so they are handled in
   <bits/libc-header-start.h>, which does not have a multiple include
   guard.  Feature test macros that can be handled from the first
   system header included are handled here.  */


/* Undefine everything, so we get a clean slate.  */
#undef	__USE_ISOC11
#undef	__USE_ISOC99
#undef	__USE_ISOC95
#undef	__USE_ISOCXX11
#undef	__USE_POSIX
#undef	__USE_POSIX2
#undef	__USE_POSIX199309
#undef	__USE_POSIX199506
#undef	__USE_XOPEN
#undef	__USE_XOPEN_EXTENDED
#undef	__USE_UNIX98
#undef	__USE_XOPEN2K
#undef	__USE_XOPEN2KXSI
#undef	__USE_XOPEN2K8
#undef	__USE_XOPEN2K8XSI
#undef	__USE_LARGEFILE
#undef	__USE_LARGEFILE64
#undef	__USE_FILE_OFFSET64
#undef	__USE_MISC
#undef	__USE_ATFILE
#undef	__USE_GNU
#undef	__USE_FORTIFY_LEVEL
#undef	__KERNEL_STRICT_NAMES
#undef	__GLIBC_USE_DEPRECATED_GETS

/* Suppress kernel-name space pollution unless user expressedly asks
   for it.  */
#ifndef _LOOSE_KERNEL_NAMES
# define __KERNEL_STRICT_NAMES
#endif

/* Convenience macro to test the version of gcc.
   Use like this:
   #if __GNUC_PREREQ (2,8)
   ... code requiring gcc 2.8 or later ...
   #endif
   Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was
   added in 2.0.  */
#if defined __GNUC__ && defined __GNUC_MINOR__
# define __GNUC_PREREQ(maj, min) \
	((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
#else
# define __GNUC_PREREQ(maj, min) 0
#endif

/* Similarly for clang.  Features added to GCC after version 4.2 may
   or may not also be available in clang, and clang's definitions of
   __GNUC(_MINOR)__ are fixed at 4 and 2 respectively.  Not all such
   features can be queried via __has_extension/__has_feature.  */
#if defined __clang_major__ && defined __clang_minor__
# define __glibc_clang_prereq(maj, min) \
  ((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
#else
# define __glibc_clang_prereq(maj, min) 0
#endif

/* Whether to use feature set F.  */
#define __GLIBC_USE(F)	__GLIBC_USE_ ## F

/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
   _DEFAULT_SOURCE.  If _DEFAULT_SOURCE is present we do not
   issue a warning; the expectation is that the source is being
   transitioned to use the new macro.  */
#if (defined _BSD_SOURCE || defined _SVID_SOURCE) \
    && !defined _DEFAULT_SOURCE
# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
# undef  _DEFAULT_SOURCE
# define _DEFAULT_SOURCE	1
#endif

/* If _GNU_SOURCE was defined by the user, turn on all the other features.  */
#ifdef _GNU_SOURCE
# undef  _ISOC95_SOURCE
# define _ISOC95_SOURCE	1
# undef  _ISOC99_SOURCE
# define _ISOC99_SOURCE	1
# undef  _ISOC11_SOURCE
# define _ISOC11_SOURCE	1
# undef  _POSIX_SOURCE
# define _POSIX_SOURCE	1
# undef  _POSIX_C_SOURCE
# define _POSIX_C_SOURCE	200809L
# undef  _XOPEN_SOURCE
# define _XOPEN_SOURCE	700
# undef  _XOPEN_SOURCE_EXTENDED
# define _XOPEN_SOURCE_EXTENDED	1
# undef	 _LARGEFILE64_SOURCE
# define _LARGEFILE64_SOURCE	1
# undef  _DEFAULT_SOURCE
# define _DEFAULT_SOURCE	1
# undef  _ATFILE_SOURCE
# define _ATFILE_SOURCE	1
#endif

/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
   define _DEFAULT_SOURCE.  */
#if (defined _DEFAULT_SOURCE					\
     || (!defined __STRICT_ANSI__				\
	 && !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE	\
	 && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE	\
	 && !defined _XOPEN_SOURCE))
# undef  _DEFAULT_SOURCE
# define _DEFAULT_SOURCE	1
#endif

/* This is to enable the ISO C11 extension.  */
#if (defined _ISOC11_SOURCE \
     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
# define __USE_ISOC11	1
#endif

/* This is to enable the ISO C99 extension.  */
#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
# define __USE_ISOC99	1
#endif

/* This is to enable the ISO C90 Amendment 1:1995 extension.  */
#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
     || (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
# define __USE_ISOC95	1
#endif

#ifdef __cplusplus
/* This is to enable compatibility for ISO C++17.  */
# if __cplusplus >= 201703L
#  define __USE_ISOC11	1
# endif
/* This is to enable compatibility for ISO C++11.
   Check the temporary macro for now, too.  */
# if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__
#  define __USE_ISOCXX11	1
#  define __USE_ISOC99	1
# endif
#endif

/* 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__					\
      || (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500))	\
     && !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
# define _POSIX_SOURCE	1
# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
#  define _POSIX_C_SOURCE	2
# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
#  define _POSIX_C_SOURCE	199506L
# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
#  define _POSIX_C_SOURCE	200112L
# else
#  define _POSIX_C_SOURCE	200809L
# endif
# define __USE_POSIX_IMPLICITLY	1
#endif

/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
   defined in all multithreaded code.  GNU libc has not required this
   for many years.  We now treat them as compatibility synonyms for
   _POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with
   comprehensive support for multithreaded code.  Using them never
   lowers the selected level of POSIX conformance, only raises it.  */
#if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \
     && (defined _REENTRANT || defined _THREAD_SAFE))
# define _POSIX_SOURCE   1
# undef  _POSIX_C_SOURCE
# define _POSIX_C_SOURCE 199506L
#endif

#if (defined _POSIX_SOURCE					\
     || (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1)	\
     || defined _XOPEN_SOURCE)
# define __USE_POSIX	1
#endif

#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
# define __USE_POSIX2	1
#endif

#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L
# define __USE_POSIX199309	1
#endif

#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L
# define __USE_POSIX199506	1
#endif

#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L
# define __USE_XOPEN2K		1
# undef __USE_ISOC95
# define __USE_ISOC95		1
# undef __USE_ISOC99
# define __USE_ISOC99		1
#endif

#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L
# define __USE_XOPEN2K8		1
# undef  _ATFILE_SOURCE
# define _ATFILE_SOURCE	1
#endif

#ifdef	_XOPEN_SOURCE
# define __USE_XOPEN	1
# if (_XOPEN_SOURCE - 0) >= 500
#  define __USE_XOPEN_EXTENDED	1
#  define __USE_UNIX98	1
#  undef _LARGEFILE_SOURCE
#  define _LARGEFILE_SOURCE	1
#  if (_XOPEN_SOURCE - 0) >= 600
#   if (_XOPEN_SOURCE - 0) >= 700
#    define __USE_XOPEN2K8	1
#    define __USE_XOPEN2K8XSI	1
#   endif
#   define __USE_XOPEN2K	1
#   define __USE_XOPEN2KXSI	1
#   undef __USE_ISOC95
#   define __USE_ISOC95		1
#   undef __USE_ISOC99
#   define __USE_ISOC99		1
#  endif
# else
#  ifdef _XOPEN_SOURCE_EXTENDED
#   define __USE_XOPEN_EXTENDED	1
#  endif
# endif
#endif

#ifdef _LARGEFILE_SOURCE
# define __USE_LARGEFILE	1
#endif

#ifdef _LARGEFILE64_SOURCE
# define __USE_LARGEFILE64	1
#endif

#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
# define __USE_FILE_OFFSET64	1
#endif

#if defined _DEFAULT_SOURCE
# define __USE_MISC	1
#endif

#ifdef	_ATFILE_SOURCE
# define __USE_ATFILE	1
#endif

#ifdef	_GNU_SOURCE
# define __USE_GNU	1
#endif

#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
#  warning _FORTIFY_SOURCE requires compiling with optimization (-O)
# elif !__GNUC_PREREQ (4, 1)
#  warning _FORTIFY_SOURCE requires GCC 4.1 or later
# elif _FORTIFY_SOURCE > 1
#  define __USE_FORTIFY_LEVEL 2
# else
#  define __USE_FORTIFY_LEVEL 1
# endif
#endif
#ifndef __USE_FORTIFY_LEVEL
# define __USE_FORTIFY_LEVEL 0
#endif

/* The function 'gets' existed in C89, but is impossible to use
   safely.  It has been removed from ISO C11 and ISO C++14.  Note: for
   compatibility with various implementations of <cstdio>, this test
   must consider only the value of __cplusplus when compiling C++.  */
#if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11
# define __GLIBC_USE_DEPRECATED_GETS 0
#else
# define __GLIBC_USE_DEPRECATED_GETS 1
#endif

/* Get definitions of __STDC_* predefined macros, if the compiler has
   not preincluded this header automatically.  */
#include <stdc-predef.h>

/* This macro indicates that the installed library is the GNU C Library.
   For historic reasons the value now is 6 and this will stay from now
   on.  The use of this variable is deprecated.  Use __GLIBC__ and
   __GLIBC_MINOR__ now (see below) when you want to test for a specific
   GNU C library version and use the values in <gnu/lib-names.h> to get
   the sonames of the shared libraries.  */
#undef  __GNU_LIBRARY__
#define __GNU_LIBRARY__ 6

/* Major and minor version number of the GNU C library package.  Use
   these macros to test for features in specific releases.  */
#define	__GLIBC__	2
#define	__GLIBC_MINOR__	28

#define __GLIBC_PREREQ(maj, min) \
	((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))

/* This is here only because every header file already includes this one.  */
#ifndef __ASSEMBLER__
# ifndef _SYS_CDEFS_H
#  include <sys/cdefs.h>
# endif

/* If we don't have __REDIRECT, prototypes will be missing if
   __USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
# if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
#  define __USE_LARGEFILE	1
#  define __USE_LARGEFILE64	1
# endif

#endif	/* !ASSEMBLER */

/* Decide whether we can define 'extern inline' functions in headers.  */
#if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
    && !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
    && defined __extern_inline
# define __USE_EXTERN_INLINES	1
#endif


/* This is here only because every header file already includes this one.
   Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
   <gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
   that will always return failure (and set errno to ENOSYS).  */
#include <gnu/stubs.h>


#endif	/* features.h  */
Commit	Line	Data
688903eb	1	/* Copyright (C) 1991-2018 Free Software Foundation, Inc.
2c6fe0bd	2	This file is part of the GNU C Library.
28f540f4	3
2c6fe0bd	4	The GNU C Library is free software; you can redistribute it and/or
41bdb6e2 AJ	5	modify it under the terms of the GNU Lesser General Public
	6	License as published by the Free Software Foundation; either
	7	version 2.1 of the License, or (at your option) any later version.
28f540f4	8
2c6fe0bd UD	9	The GNU C Library is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
41bdb6e2	12	Lesser General Public License for more details.
28f540f4	13
41bdb6e2	14	You should have received a copy of the GNU Lesser General Public
59ba27a6 PE	15	License along with the GNU C Library; if not, see
59ba27a6 PE	16	<http://www.gnu.org/licenses/>. */
28f540f4 RM	17
28f540f4 RM	18	#ifndef _FEATURES_H
28f540f4 RM	19	#define _FEATURES_H 1
	20
	21	/* These are defined by the user (or the compiler)
	22	to specify the desired environment:
	23
d38cd08c	24	__STRICT_ANSI__ ISO Standard C.
ec751a23	25	_ISOC99_SOURCE Extensions to ISO C89 from ISO C99.
d7809905	26	_ISOC11_SOURCE Extensions to ISO C99 from ISO C11.
c0307377 ZW	27	__STDC_WANT_LIB_EXT2__
	28	Extensions to ISO C99 from TR 27431-2:2010.
	29	__STDC_WANT_IEC_60559_BFP_EXT__
	30	Extensions to ISO C11 from TS 18661-1:2014.
	31	__STDC_WANT_IEC_60559_FUNCS_EXT__
	32	Extensions to ISO C11 from TS 18661-4:2015.
4fc12f0e PM	33	__STDC_WANT_IEC_60559_TYPES_EXT__
4fc12f0e PM	34	Extensions to ISO C11 from TS 18661-3:2015.
c0307377	35
28f540f4	36	_POSIX_SOURCE IEEE Std 1003.1.
6d52618b	37	_POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
118bad87	38	if >=199309L, add IEEE Std 1003.1b-1993;
7a80496f UD	39	if >=199506L, add IEEE Std 1003.1c-1995;
7a80496f UD	40	if >=200112L, all of IEEE 1003.1-2004
3e6b0a28	41	if >=200809L, all of IEEE 1003.1-2008
a5a0310d	42	_XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if
925e31d9	43	Single Unix conformance is wanted, to 600 for the
3e6b0a28	44	sixth revision, to 700 for the seventh revision.
2c6fe0bd	45	_XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
dfd2257a UD	46	_LARGEFILE_SOURCE Some more functions for correct standard I/O.
	47	_LARGEFILE64_SOURCE Additional functionality from LFS for large files.
	48	_FILE_OFFSET_BITS=N Select default filesystem interface.
0b8f25bb	49	_ATFILE_SOURCE Additional *at interfaces.
28f540f4	50	_GNU_SOURCE All of the above, plus GNU extensions.
c688b419 JM	51	_DEFAULT_SOURCE The default set of features (taking precedence over
c688b419 JM	52	__STRICT_ANSI__).
c0307377 ZW	53
	54	_FORTIFY_SOURCE Add security hardening to many library functions.
	55	Set to 1 or 2; 2 performs stricter checks than 1.
	56
	57	_REENTRANT, _THREAD_SAFE
	58	Obsolete; equivalent to _POSIX_C_SOURCE=199506L.
28f540f4	59
c688b419 JM	60	The `-ansi' switch to the GNU C compiler, and standards conformance
	61	options such as `-std=c99', define __STRICT_ANSI__. If none of
	62	these are defined, or if _DEFAULT_SOURCE is defined, the default is
c941736c JM	63	to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
	64	200809L, as well as enabling miscellaneous functions from BSD and
	65	SVID. If more than one of these are defined, they accumulate. For
	66	example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together
	67	give you ISO C, 1003.1, and 1003.2, but nothing else.
28f540f4 RM	68
	69	These are defined by this file and are used by the
	70	header files to decide what to declare or define:
	71
48789000 JM	72	__GLIBC_USE (F) Define things from feature set F. This is defined
	73	to 1 or 0; the subsequent macros are either defined
	74	or undefined, and those tests should be moved to
	75	__GLIBC_USE.
d7809905	76	__USE_ISOC11 Define ISO C11 things.
ec751a23	77	__USE_ISOC99 Define ISO C99 things.
087722b8	78	__USE_ISOC95 Define ISO C90 AMD1 (C95) things.
d6c064e9	79	__USE_ISOCXX11 Define ISO C++11 things.
28f540f4 RM	80	__USE_POSIX Define IEEE Std 1003.1 things.
28f540f4 RM	81	__USE_POSIX2 Define IEEE Std 1003.2 things.
4a582094 UD	82	__USE_POSIX199309 Define IEEE Std 1003.1, and .1b things.
4a582094 UD	83	__USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things.
2c6fe0bd UD	84	__USE_XOPEN Define XPG things.
2c6fe0bd UD	85	__USE_XOPEN_EXTENDED Define X/Open Unix things.
a5a0310d	86	__USE_UNIX98 Define Single Unix V2 things.
925e31d9	87	__USE_XOPEN2K Define XPG6 things.
f095bb72	88	__USE_XOPEN2KXSI Define XPG6 XSI things.
81489b2e	89	__USE_XOPEN2K8 Define XPG7 things.
f095bb72	90	__USE_XOPEN2K8XSI Define XPG7 XSI things.
925e31d9	91	__USE_LARGEFILE Define correct standard I/O things.
dfd2257a UD	92	__USE_LARGEFILE64 Define LFS things with separate names.
dfd2257a UD	93	__USE_FILE_OFFSET64 Define 64bit interface as default.
498afc54	94	__USE_MISC Define things from 4.3BSD or System V Unix.
0b8f25bb	95	__USE_ATFILE Define at interfaces and AT_ constants for them.
28f540f4	96	__USE_GNU Define GNU extensions.
b5cc329c	97	__USE_FORTIFY_LEVEL Additional security measures used, according to level.
28f540f4	98
d38cd08c UD	99	The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
	100	defined by this file unconditionally. `__GNU_LIBRARY__' is provided
	101	only for compatibility. All new code should use the other symbols
	102	to test for features.
28f540f4	103
28f540f4 RM	104	All macros listed above as possibly being defined by this file are
	105	explicitly undefined if they are not explicitly defined.
	106	Feature-test macros that are not defined by the user or compiler
	107	but are implied by the other feature-test macros defined (or by the
48789000 JM	108	lack of any definitions) are defined by the file.
	109
	110	ISO C feature test macros depend on the definition of the macro
	111	when an affected header is included, not when the first system
	112	header is included, and so they are handled in
	113	<bits/libc-header-start.h>, which does not have a multiple include
	114	guard. Feature test macros that can be handled from the first
	115	system header included are handled here. */
28f540f4 RM	116
	117
	118	/* Undefine everything, so we get a clean slate. */
d7809905	119	#undef __USE_ISOC11
ec751a23	120	#undef __USE_ISOC99
087722b8	121	#undef __USE_ISOC95
8fd8ff3b	122	#undef __USE_ISOCXX11
28f540f4 RM	123	#undef __USE_POSIX
28f540f4 RM	124	#undef __USE_POSIX2
6d52618b	125	#undef __USE_POSIX199309
4a582094	126	#undef __USE_POSIX199506
2c6fe0bd UD	127	#undef __USE_XOPEN
2c6fe0bd UD	128	#undef __USE_XOPEN_EXTENDED
dfd2257a	129	#undef __USE_UNIX98
24d6fe58	130	#undef __USE_XOPEN2K
f095bb72	131	#undef __USE_XOPEN2KXSI
3e6b0a28	132	#undef __USE_XOPEN2K8
f095bb72	133	#undef __USE_XOPEN2K8XSI
dfd2257a UD	134	#undef __USE_LARGEFILE
	135	#undef __USE_LARGEFILE64
	136	#undef __USE_FILE_OFFSET64
28f540f4	137	#undef __USE_MISC
0b8f25bb	138	#undef __USE_ATFILE
28f540f4	139	#undef __USE_GNU
b5cc329c	140	#undef __USE_FORTIFY_LEVEL
a1470b6f	141	#undef __KERNEL_STRICT_NAMES
7caa5054	142	#undef __GLIBC_USE_DEPRECATED_GETS
28f540f4	143
a1470b6f	144	/* Suppress kernel-name space pollution unless user expressedly asks
2c6fe0bd	145	for it. */
a1470b6f RM	146	#ifndef _LOOSE_KERNEL_NAMES
	147	# define __KERNEL_STRICT_NAMES
	148	#endif
28f540f4	149
cab4d74b ZW	150	/* Convenience macro to test the version of gcc.
cab4d74b ZW	151	Use like this:
b5cc329c UD	152	#if __GNUC_PREREQ (2,8)
	153	... code requiring gcc 2.8 or later ...
	154	#endif
cab4d74b ZW	155	Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was
cab4d74b ZW	156	added in 2.0. */
b5cc329c UD	157	#if defined __GNUC__ && defined __GNUC_MINOR__
	158	# define __GNUC_PREREQ(maj, min) \
	159	((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
	160	#else
	161	# define __GNUC_PREREQ(maj, min) 0
	162	#endif
	163
cab4d74b ZW	164	/* Similarly for clang. Features added to GCC after version 4.2 may
	165	or may not also be available in clang, and clang's definitions of
	166	__GNUC(_MINOR)__ are fixed at 4 and 2 respectively. Not all such
	167	features can be queried via __has_extension/__has_feature. */
	168	#if defined __clang_major__ && defined __clang_minor__
	169	# define __glibc_clang_prereq(maj, min) \
	170	((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
	171	#else
	172	# define __glibc_clang_prereq(maj, min) 0
	173	#endif
	174
48789000 JM	175	/* Whether to use feature set F. */
	176	#define __GLIBC_USE(F) __GLIBC_USE_ ## F
	177
c941736c	178	/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
ade40b10 CD	179	_DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not
	180	issue a warning; the expectation is that the source is being
	181	transitioned to use the new macro. */
	182	#if (defined _BSD_SOURCE \|\| defined _SVID_SOURCE) \
	183	&& !defined _DEFAULT_SOURCE
c941736c JM	184	# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
	185	# undef _DEFAULT_SOURCE
	186	# define _DEFAULT_SOURCE 1
	187	#endif
28f540f4	188
59dd8641 RM	189	/* If _GNU_SOURCE was defined by the user, turn on all the other features. */
59dd8641 RM	190	#ifdef _GNU_SOURCE
e531ede5 UD	191	# undef _ISOC95_SOURCE
e531ede5 UD	192	# define _ISOC95_SOURCE 1
ec751a23 UD	193	# undef _ISOC99_SOURCE
ec751a23 UD	194	# define _ISOC99_SOURCE 1
d7809905 UD	195	# undef _ISOC11_SOURCE
d7809905 UD	196	# define _ISOC11_SOURCE 1
5107cf1d UD	197	# undef _POSIX_SOURCE
	198	# define _POSIX_SOURCE 1
	199	# undef _POSIX_C_SOURCE
3e6b0a28	200	# define _POSIX_C_SOURCE 200809L
5107cf1d	201	# undef _XOPEN_SOURCE
3e6b0a28	202	# define _XOPEN_SOURCE 700
5107cf1d UD	203	# undef _XOPEN_SOURCE_EXTENDED
5107cf1d UD	204	# define _XOPEN_SOURCE_EXTENDED 1
dfd2257a UD	205	# undef _LARGEFILE64_SOURCE
dfd2257a UD	206	# define _LARGEFILE64_SOURCE 1
c688b419 JM	207	# undef _DEFAULT_SOURCE
c688b419 JM	208	# define _DEFAULT_SOURCE 1
0b8f25bb RM	209	# undef _ATFILE_SOURCE
0b8f25bb RM	210	# define _ATFILE_SOURCE 1
59dd8641	211	#endif
28f540f4	212
c688b419	213	/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
498afc54	214	define _DEFAULT_SOURCE. */
c688b419 JM	215	#if (defined _DEFAULT_SOURCE \
c688b419 JM	216	\|\| (!defined __STRICT_ANSI__ \
862b4502	217	&& !defined _ISOC99_SOURCE && !defined _ISOC11_SOURCE \
c688b419	218	&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \
498afc54	219	&& !defined _XOPEN_SOURCE))
c688b419 JM	220	# undef _DEFAULT_SOURCE
c688b419 JM	221	# define _DEFAULT_SOURCE 1
28f540f4 RM	222	#endif
28f540f4 RM	223
d7809905 UD	224	/* This is to enable the ISO C11 extension. */
	225	#if (defined _ISOC11_SOURCE \
	226	\|\| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
c0e87cc0 UD	227	# define __USE_ISOC11 1
c0e87cc0 UD	228	#endif
d7809905 UD	229
	230	/* This is to enable the ISO C99 extension. */
	231	#if (defined _ISOC99_SOURCE \|\| defined _ISOC11_SOURCE \
47a81620	232	\|\| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
ec751a23	233	# define __USE_ISOC99 1
2f6d1f1b UD	234	#endif
2f6d1f1b UD	235
087722b8	236	/* This is to enable the ISO C90 Amendment 1:1995 extension. */
d7809905	237	#if (defined _ISOC99_SOURCE \|\| defined _ISOC11_SOURCE \
087722b8 UD	238	\|\| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
	239	# define __USE_ISOC95 1
	240	#endif
	241
d6c064e9 JW	242	#ifdef __cplusplus
	243	/* This is to enable compatibility for ISO C++17. */
	244	# if __cplusplus >= 201703L
	245	# define __USE_ISOC11 1
	246	# endif
8fd8ff3b	247	/* This is to enable compatibility for ISO C++11.
d6c064e9 JW	248	Check the temporary macro for now, too. */
	249	# if __cplusplus >= 201103L \|\| defined __GXX_EXPERIMENTAL_CXX0X__
	250	# define __USE_ISOCXX11 1
	251	# define __USE_ISOC99 1
	252	# endif
8fd8ff3b UD	253	#endif
8fd8ff3b UD	254
c688b419 JM	255	/* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE
	256	is defined, use POSIX.1-2008 (or another version depending on
	257	_XOPEN_SOURCE). */
	258	#ifdef _DEFAULT_SOURCE
	259	# if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE
	260	# define __USE_POSIX_IMPLICITLY 1
	261	# endif
	262	# undef _POSIX_SOURCE
	263	# define _POSIX_SOURCE 1
	264	# undef _POSIX_C_SOURCE
	265	# define _POSIX_C_SOURCE 200809L
	266	#endif
c0307377	267
f248238c JM	268	#if ((!defined __STRICT_ANSI__ \
	269	\|\| (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \
	270	&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
5107cf1d	271	# define _POSIX_SOURCE 1
925e31d9	272	# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
5107cf1d	273	# define _POSIX_C_SOURCE 2
1676aaef	274	# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
a334319f	275	# define _POSIX_C_SOURCE 199506L
3e6b0a28	276	# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
1676aaef	277	# define _POSIX_C_SOURCE 200112L
3e6b0a28 UD	278	# else
3e6b0a28 UD	279	# define _POSIX_C_SOURCE 200809L
5107cf1d	280	# endif
2e6d6bac	281	# define __USE_POSIX_IMPLICITLY 1
28f540f4 RM	282	#endif
28f540f4 RM	283
c0307377 ZW	284	/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
	285	defined in all multithreaded code. GNU libc has not required this
	286	for many years. We now treat them as compatibility synonyms for
	287	_POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with
	288	comprehensive support for multithreaded code. Using them never
	289	lowers the selected level of POSIX conformance, only raises it. */
	290	#if ((!defined _POSIX_C_SOURCE \|\| (_POSIX_C_SOURCE - 0) < 199506L) \
	291	&& (defined _REENTRANT \|\| defined _THREAD_SAFE))
	292	# define _POSIX_SOURCE 1
	293	# undef _POSIX_C_SOURCE
	294	# define _POSIX_C_SOURCE 199506L
	295	#endif
	296
f248238c JM	297	#if (defined _POSIX_SOURCE \
	298	\|\| (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \
	299	\|\| defined _XOPEN_SOURCE)
5107cf1d	300	# define __USE_POSIX 1
28f540f4 RM	301	#endif
28f540f4 RM	302
d38cd08c	303	#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 \|\| defined _XOPEN_SOURCE
5107cf1d	304	# define __USE_POSIX2 1
28f540f4 RM	305	#endif
28f540f4 RM	306
f248238c	307	#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L
9756dfe1	308	# define __USE_POSIX199309 1
6d52618b UD	309	#endif
6d52618b UD	310
f248238c	311	#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L
4a582094 UD	312	# define __USE_POSIX199506 1
	313	#endif
	314
f248238c	315	#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L
23ae6451	316	# define __USE_XOPEN2K 1
e531ede5 UD	317	# undef __USE_ISOC95
e531ede5 UD	318	# define __USE_ISOC95 1
c163ee23 UD	319	# undef __USE_ISOC99
c163ee23 UD	320	# define __USE_ISOC99 1
23ae6451 UD	321	#endif
23ae6451 UD	322
f248238c	323	#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L
3e6b0a28 UD	324	# define __USE_XOPEN2K8 1
	325	# undef _ATFILE_SOURCE
	326	# define _ATFILE_SOURCE 1
	327	#endif
	328
2c6fe0bd	329	#ifdef _XOPEN_SOURCE
5107cf1d	330	# define __USE_XOPEN 1
219aa9e9	331	# if (_XOPEN_SOURCE - 0) >= 500
5107cf1d	332	# define __USE_XOPEN_EXTENDED 1
a5a0310d	333	# define __USE_UNIX98 1
dfd2257a UD	334	# undef _LARGEFILE_SOURCE
dfd2257a UD	335	# define _LARGEFILE_SOURCE 1
925e31d9	336	# if (_XOPEN_SOURCE - 0) >= 600
3e6b0a28 UD	337	# if (_XOPEN_SOURCE - 0) >= 700
3e6b0a28 UD	338	# define __USE_XOPEN2K8 1
f095bb72	339	# define __USE_XOPEN2K8XSI 1
3e6b0a28	340	# endif
219aa9e9	341	# define __USE_XOPEN2K 1
f095bb72	342	# define __USE_XOPEN2KXSI 1
e531ede5 UD	343	# undef __USE_ISOC95
e531ede5 UD	344	# define __USE_ISOC95 1
91bc38d0 UD	345	# undef __USE_ISOC99
91bc38d0 UD	346	# define __USE_ISOC99 1
219aa9e9	347	# endif
a5a0310d UD	348	# else
	349	# ifdef _XOPEN_SOURCE_EXTENDED
	350	# define __USE_XOPEN_EXTENDED 1
	351	# endif
5107cf1d	352	# endif
2c6fe0bd UD	353	#endif
2c6fe0bd UD	354
dfd2257a UD	355	#ifdef _LARGEFILE_SOURCE
	356	# define __USE_LARGEFILE 1
	357	#endif
	358
	359	#ifdef _LARGEFILE64_SOURCE
	360	# define __USE_LARGEFILE64 1
	361	#endif
	362
	363	#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
	364	# define __USE_FILE_OFFSET64 1
	365	#endif
	366
498afc54	367	#if defined _DEFAULT_SOURCE
5107cf1d	368	# define __USE_MISC 1
28f540f4 RM	369	#endif
28f540f4 RM	370
0b8f25bb RM	371	#ifdef _ATFILE_SOURCE
	372	# define __USE_ATFILE 1
	373	#endif
	374
28f540f4	375	#ifdef _GNU_SOURCE
5107cf1d	376	# define __USE_GNU 1
28f540f4 RM	377	#endif
28f540f4 RM	378
05c2c961 RMG	379	#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
	380	# if !defined __OPTIMIZE__ \|\| __OPTIMIZE__ <= 0
	381	# warning _FORTIFY_SOURCE requires compiling with optimization (-O)
	382	# elif !__GNUC_PREREQ (4, 1)
	383	# warning _FORTIFY_SOURCE requires GCC 4.1 or later
	384	# elif _FORTIFY_SOURCE > 1
a334319f	385	# define __USE_FORTIFY_LEVEL 2
faa26ad4 RM	386	# else
faa26ad4 RM	387	# define __USE_FORTIFY_LEVEL 1
b5cc329c	388	# endif
05c2c961 RMG	389	#endif
05c2c961 RMG	390	#ifndef __USE_FORTIFY_LEVEL
faa26ad4	391	# define __USE_FORTIFY_LEVEL 0
b5cc329c UD	392	#endif
b5cc329c UD	393
7caa5054 ZW	394	/* The function 'gets' existed in C89, but is impossible to use
	395	safely. It has been removed from ISO C11 and ISO C++14. Note: for
	396	compatibility with various implementations of <cstdio>, this test
	397	must consider only the value of __cplusplus when compiling C++. */
	398	#if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11
	399	# define __GLIBC_USE_DEPRECATED_GETS 0
	400	#else
	401	# define __GLIBC_USE_DEPRECATED_GETS 1
	402	#endif
	403
ff3b3d82 JM	404	/* Get definitions of __STDC_* predefined macros, if the compiler has
	405	not preincluded this header automatically. */
	406	#include <stdc-predef.h>
91bc38d0	407
ba1ffaa1 UD	408	/* This macro indicates that the installed library is the GNU C Library.
	409	For historic reasons the value now is 6 and this will stay from now
	410	on. The use of this variable is deprecated. Use __GLIBC__ and
	411	__GLIBC_MINOR__ now (see below) when you want to test for a specific
	412	GNU C library version and use the values in <gnu/lib-names.h> to get
	413	the sonames of the shared libraries. */
	414	#undef __GNU_LIBRARY__
	415	#define __GNU_LIBRARY__ 6
	416
	417	/* Major and minor version number of the GNU C library package. Use
	418	these macros to test for features in specific releases. */
	419	#define __GLIBC__ 2
3c03baca	420	#define __GLIBC_MINOR__ 28
28f540f4	421
f042f18f UD	422	#define __GLIBC_PREREQ(maj, min) \
f042f18f UD	423	((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
4360eafd	424
28f540f4	425	/* This is here only because every header file already includes this one. */
edf5b2d7	426	#ifndef __ASSEMBLER__
95589177 UD	427	# ifndef _SYS_CDEFS_H
	428	# include <sys/cdefs.h>
	429	# endif
01cad722 UD	430
	431	/* If we don't have __REDIRECT, prototypes will be missing if
	432	__USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
	433	# if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
4152ed15 UD	434	# define __USE_LARGEFILE 1
4152ed15 UD	435	# define __USE_LARGEFILE64 1
01cad722 UD	436	# endif
01cad722 UD	437
eedbbe58 UD	438	#endif /* !ASSEMBLER */
	439
	440	/* Decide whether we can define 'extern inline' functions in headers. */
07c416ed	441	#if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
de1c3ebb UD	442	&& !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
de1c3ebb UD	443	&& defined __extern_inline
eedbbe58	444	# define __USE_EXTERN_INLINES 1
edf5b2d7	445	#endif
28f540f4	446
28f540f4	447
ce460d04 RM	448	/* This is here only because every header file already includes this one.
	449	Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
	450	<gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
	451	that will always return failure (and set errno to ENOSYS). */
	452	#include <gnu/stubs.h>
28f540f4	453
28f540f4	454
6ed0492f	455	#endif /* features.h */