456 lines
15 KiB
C
456 lines
15 KiB
C
/* Copyright (C) 1991-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _FEATURES_H
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#define _FEATURES_H 1
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/* These are defined by the user (or the compiler)
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to specify the desired environment:
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__STRICT_ANSI__ ISO Standard C.
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_ISOC99_SOURCE Extensions to ISO C89 from ISO C99.
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_ISOC11_SOURCE Extensions to ISO C99 from ISO C11.
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__STDC_WANT_LIB_EXT2__
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Extensions to ISO C99 from TR 27431-2:2010.
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__STDC_WANT_IEC_60559_BFP_EXT__
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Extensions to ISO C11 from TS 18661-1:2014.
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__STDC_WANT_IEC_60559_FUNCS_EXT__
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Extensions to ISO C11 from TS 18661-4:2015.
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__STDC_WANT_IEC_60559_TYPES_EXT__
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Extensions to ISO C11 from TS 18661-3:2015.
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_POSIX_SOURCE IEEE Std 1003.1.
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_POSIX_C_SOURCE If ==1, like _POSIX_SOURCE; if >=2 add IEEE Std 1003.2;
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if >=199309L, add IEEE Std 1003.1b-1993;
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if >=199506L, add IEEE Std 1003.1c-1995;
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if >=200112L, all of IEEE 1003.1-2004
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if >=200809L, all of IEEE 1003.1-2008
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_XOPEN_SOURCE Includes POSIX and XPG things. Set to 500 if
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Single Unix conformance is wanted, to 600 for the
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sixth revision, to 700 for the seventh revision.
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_XOPEN_SOURCE_EXTENDED XPG things and X/Open Unix extensions.
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_LARGEFILE_SOURCE Some more functions for correct standard I/O.
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_LARGEFILE64_SOURCE Additional functionality from LFS for large files.
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_FILE_OFFSET_BITS=N Select default filesystem interface.
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_ATFILE_SOURCE Additional *at interfaces.
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_GNU_SOURCE All of the above, plus GNU extensions.
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_DEFAULT_SOURCE The default set of features (taking precedence over
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__STRICT_ANSI__).
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_FORTIFY_SOURCE Add security hardening to many library functions.
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Set to 1 or 2; 2 performs stricter checks than 1.
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_REENTRANT, _THREAD_SAFE
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Obsolete; equivalent to _POSIX_C_SOURCE=199506L.
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The `-ansi' switch to the GNU C compiler, and standards conformance
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options such as `-std=c99', define __STRICT_ANSI__. If none of
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these are defined, or if _DEFAULT_SOURCE is defined, the default is
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to have _POSIX_SOURCE set to one and _POSIX_C_SOURCE set to
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200809L, as well as enabling miscellaneous functions from BSD and
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SVID. If more than one of these are defined, they accumulate. For
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example __STRICT_ANSI__, _POSIX_SOURCE and _POSIX_C_SOURCE together
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give you ISO C, 1003.1, and 1003.2, but nothing else.
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These are defined by this file and are used by the
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header files to decide what to declare or define:
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__GLIBC_USE (F) Define things from feature set F. This is defined
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to 1 or 0; the subsequent macros are either defined
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or undefined, and those tests should be moved to
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__GLIBC_USE.
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__USE_ISOC11 Define ISO C11 things.
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__USE_ISOC99 Define ISO C99 things.
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__USE_ISOC95 Define ISO C90 AMD1 (C95) things.
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__USE_ISOCXX11 Define ISO C++11 things.
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__USE_POSIX Define IEEE Std 1003.1 things.
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__USE_POSIX2 Define IEEE Std 1003.2 things.
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__USE_POSIX199309 Define IEEE Std 1003.1, and .1b things.
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__USE_POSIX199506 Define IEEE Std 1003.1, .1b, .1c and .1i things.
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__USE_XOPEN Define XPG things.
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__USE_XOPEN_EXTENDED Define X/Open Unix things.
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__USE_UNIX98 Define Single Unix V2 things.
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__USE_XOPEN2K Define XPG6 things.
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__USE_XOPEN2KXSI Define XPG6 XSI things.
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__USE_XOPEN2K8 Define XPG7 things.
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__USE_XOPEN2K8XSI Define XPG7 XSI things.
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__USE_LARGEFILE Define correct standard I/O things.
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__USE_LARGEFILE64 Define LFS things with separate names.
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__USE_FILE_OFFSET64 Define 64bit interface as default.
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__USE_MISC Define things from 4.3BSD or System V Unix.
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__USE_ATFILE Define *at interfaces and AT_* constants for them.
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__USE_GNU Define GNU extensions.
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__USE_FORTIFY_LEVEL Additional security measures used, according to level.
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The macros `__GNU_LIBRARY__', `__GLIBC__', and `__GLIBC_MINOR__' are
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defined by this file unconditionally. `__GNU_LIBRARY__' is provided
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only for compatibility. All new code should use the other symbols
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to test for features.
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All macros listed above as possibly being defined by this file are
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explicitly undefined if they are not explicitly defined.
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Feature-test macros that are not defined by the user or compiler
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but are implied by the other feature-test macros defined (or by the
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lack of any definitions) are defined by the file.
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ISO C feature test macros depend on the definition of the macro
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when an affected header is included, not when the first system
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header is included, and so they are handled in
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<bits/libc-header-start.h>, which does not have a multiple include
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guard. Feature test macros that can be handled from the first
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system header included are handled here. */
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/* Undefine everything, so we get a clean slate. */
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#undef __USE_ISOC11
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#undef __USE_ISOC99
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#undef __USE_ISOC95
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#undef __USE_ISOCXX11
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#undef __USE_POSIX
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#undef __USE_POSIX2
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#undef __USE_POSIX199309
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#undef __USE_POSIX199506
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#undef __USE_XOPEN
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#undef __USE_XOPEN_EXTENDED
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#undef __USE_UNIX98
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#undef __USE_XOPEN2K
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#undef __USE_XOPEN2KXSI
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#undef __USE_XOPEN2K8
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#undef __USE_XOPEN2K8XSI
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#undef __USE_LARGEFILE
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#undef __USE_LARGEFILE64
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#undef __USE_FILE_OFFSET64
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#undef __USE_MISC
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#undef __USE_ATFILE
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#undef __USE_GNU
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#undef __USE_FORTIFY_LEVEL
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#undef __KERNEL_STRICT_NAMES
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#undef __GLIBC_USE_DEPRECATED_GETS
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/* Suppress kernel-name space pollution unless user expressedly asks
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for it. */
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#ifndef _LOOSE_KERNEL_NAMES
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# define __KERNEL_STRICT_NAMES
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#endif
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/* Convenience macro to test the version of gcc.
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Use like this:
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#if __GNUC_PREREQ (2,8)
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... code requiring gcc 2.8 or later ...
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#endif
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Note: only works for GCC 2.0 and later, because __GNUC_MINOR__ was
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added in 2.0. */
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#if defined __GNUC__ && defined __GNUC_MINOR__
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# define __GNUC_PREREQ(maj, min) \
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((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
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#else
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# define __GNUC_PREREQ(maj, min) 0
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#endif
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/* Similarly for clang. Features added to GCC after version 4.2 may
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or may not also be available in clang, and clang's definitions of
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__GNUC(_MINOR)__ are fixed at 4 and 2 respectively. Not all such
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features can be queried via __has_extension/__has_feature. */
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#if defined __clang_major__ && defined __clang_minor__
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# define __glibc_clang_prereq(maj, min) \
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((__clang_major__ << 16) + __clang_minor__ >= ((maj) << 16) + (min))
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#else
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# define __glibc_clang_prereq(maj, min) 0
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#endif
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/* Whether to use feature set F. */
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#define __GLIBC_USE(F) __GLIBC_USE_ ## F
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/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
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_DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not
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issue a warning; the expectation is that the source is being
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transitioned to use the new macro. */
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#if (defined _BSD_SOURCE || defined _SVID_SOURCE) \
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&& !defined _DEFAULT_SOURCE
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# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
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# undef _DEFAULT_SOURCE
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# define _DEFAULT_SOURCE 1
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#endif
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/* If _GNU_SOURCE was defined by the user, turn on all the other features. */
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#ifdef _GNU_SOURCE
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# undef _ISOC95_SOURCE
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# define _ISOC95_SOURCE 1
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# undef _ISOC99_SOURCE
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# define _ISOC99_SOURCE 1
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# undef _ISOC11_SOURCE
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# define _ISOC11_SOURCE 1
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# undef _POSIX_SOURCE
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# define _POSIX_SOURCE 1
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# undef _POSIX_C_SOURCE
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# define _POSIX_C_SOURCE 200809L
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# undef _XOPEN_SOURCE
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# define _XOPEN_SOURCE 700
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# undef _XOPEN_SOURCE_EXTENDED
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# define _XOPEN_SOURCE_EXTENDED 1
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# undef _LARGEFILE64_SOURCE
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# define _LARGEFILE64_SOURCE 1
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# undef _DEFAULT_SOURCE
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# define _DEFAULT_SOURCE 1
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# undef _ATFILE_SOURCE
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# define _ATFILE_SOURCE 1
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#endif
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/* If nothing (other than _GNU_SOURCE and _DEFAULT_SOURCE) is defined,
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define _DEFAULT_SOURCE. */
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#if (defined _DEFAULT_SOURCE \
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|| (!defined __STRICT_ANSI__ \
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&& !defined _ISOC99_SOURCE \
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&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE \
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&& !defined _XOPEN_SOURCE))
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# undef _DEFAULT_SOURCE
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# define _DEFAULT_SOURCE 1
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#endif
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/* This is to enable the ISO C11 extension. */
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#if (defined _ISOC11_SOURCE \
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|| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 201112L))
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# define __USE_ISOC11 1
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#endif
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/* This is to enable the ISO C99 extension. */
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#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
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|| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199901L))
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# define __USE_ISOC99 1
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#endif
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/* This is to enable the ISO C90 Amendment 1:1995 extension. */
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#if (defined _ISOC99_SOURCE || defined _ISOC11_SOURCE \
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|| (defined __STDC_VERSION__ && __STDC_VERSION__ >= 199409L))
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# define __USE_ISOC95 1
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#endif
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#ifdef __cplusplus
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/* This is to enable compatibility for ISO C++17. */
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# if __cplusplus >= 201703L
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# define __USE_ISOC11 1
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# endif
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/* This is to enable compatibility for ISO C++11.
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Check the temporary macro for now, too. */
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# if __cplusplus >= 201103L || defined __GXX_EXPERIMENTAL_CXX0X__
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# define __USE_ISOCXX11 1
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# define __USE_ISOC99 1
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# endif
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#endif
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/* If none of the ANSI/POSIX macros are defined, or if _DEFAULT_SOURCE
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is defined, use POSIX.1-2008 (or another version depending on
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_XOPEN_SOURCE). */
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#ifdef _DEFAULT_SOURCE
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# if !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE
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# define __USE_POSIX_IMPLICITLY 1
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# endif
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# undef _POSIX_SOURCE
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# define _POSIX_SOURCE 1
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# undef _POSIX_C_SOURCE
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# define _POSIX_C_SOURCE 200809L
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#endif
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#if ((!defined __STRICT_ANSI__ \
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|| (defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) >= 500)) \
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&& !defined _POSIX_SOURCE && !defined _POSIX_C_SOURCE)
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# define _POSIX_SOURCE 1
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# if defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 500
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# define _POSIX_C_SOURCE 2
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# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 600
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# define _POSIX_C_SOURCE 199506L
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# elif defined _XOPEN_SOURCE && (_XOPEN_SOURCE - 0) < 700
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# define _POSIX_C_SOURCE 200112L
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# else
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# define _POSIX_C_SOURCE 200809L
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# endif
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# define __USE_POSIX_IMPLICITLY 1
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#endif
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/* Some C libraries once required _REENTRANT and/or _THREAD_SAFE to be
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defined in all multithreaded code. GNU libc has not required this
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for many years. We now treat them as compatibility synonyms for
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_POSIX_C_SOURCE=199506L, which is the earliest level of POSIX with
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comprehensive support for multithreaded code. Using them never
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lowers the selected level of POSIX conformance, only raises it. */
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#if ((!defined _POSIX_C_SOURCE || (_POSIX_C_SOURCE - 0) < 199506L) \
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&& (defined _REENTRANT || defined _THREAD_SAFE))
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# define _POSIX_SOURCE 1
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# undef _POSIX_C_SOURCE
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# define _POSIX_C_SOURCE 199506L
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#endif
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#if (defined _POSIX_SOURCE \
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|| (defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 1) \
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|| defined _XOPEN_SOURCE)
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# define __USE_POSIX 1
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#endif
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#if defined _POSIX_C_SOURCE && _POSIX_C_SOURCE >= 2 || defined _XOPEN_SOURCE
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# define __USE_POSIX2 1
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#endif
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#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199309L
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# define __USE_POSIX199309 1
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#endif
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#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 199506L
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# define __USE_POSIX199506 1
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#endif
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#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200112L
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# define __USE_XOPEN2K 1
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# undef __USE_ISOC95
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# define __USE_ISOC95 1
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# undef __USE_ISOC99
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# define __USE_ISOC99 1
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#endif
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#if defined _POSIX_C_SOURCE && (_POSIX_C_SOURCE - 0) >= 200809L
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# define __USE_XOPEN2K8 1
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# undef _ATFILE_SOURCE
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# define _ATFILE_SOURCE 1
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#endif
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#ifdef _XOPEN_SOURCE
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# define __USE_XOPEN 1
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# if (_XOPEN_SOURCE - 0) >= 500
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# define __USE_XOPEN_EXTENDED 1
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# define __USE_UNIX98 1
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# undef _LARGEFILE_SOURCE
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# define _LARGEFILE_SOURCE 1
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# if (_XOPEN_SOURCE - 0) >= 600
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# if (_XOPEN_SOURCE - 0) >= 700
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# define __USE_XOPEN2K8 1
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# define __USE_XOPEN2K8XSI 1
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# endif
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# define __USE_XOPEN2K 1
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# define __USE_XOPEN2KXSI 1
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# undef __USE_ISOC95
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# define __USE_ISOC95 1
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# undef __USE_ISOC99
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# define __USE_ISOC99 1
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# endif
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# else
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# ifdef _XOPEN_SOURCE_EXTENDED
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# define __USE_XOPEN_EXTENDED 1
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# endif
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# endif
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#endif
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#ifdef _LARGEFILE_SOURCE
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# define __USE_LARGEFILE 1
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#endif
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#ifdef _LARGEFILE64_SOURCE
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# define __USE_LARGEFILE64 1
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#endif
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#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
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# define __USE_FILE_OFFSET64 1
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#endif
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#if defined _DEFAULT_SOURCE
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# define __USE_MISC 1
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#endif
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#ifdef _ATFILE_SOURCE
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# define __USE_ATFILE 1
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#endif
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#ifdef _GNU_SOURCE
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# define __USE_GNU 1
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#endif
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#if defined _FORTIFY_SOURCE && _FORTIFY_SOURCE > 0
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# if !defined __OPTIMIZE__ || __OPTIMIZE__ <= 0
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# warning _FORTIFY_SOURCE requires compiling with optimization (-O)
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# elif !__GNUC_PREREQ (4, 1)
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# warning _FORTIFY_SOURCE requires GCC 4.1 or later
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# elif _FORTIFY_SOURCE > 1
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# define __USE_FORTIFY_LEVEL 2
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# else
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# define __USE_FORTIFY_LEVEL 1
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# endif
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#endif
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#ifndef __USE_FORTIFY_LEVEL
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# define __USE_FORTIFY_LEVEL 0
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#endif
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/* The function 'gets' existed in C89, but is impossible to use
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safely. It has been removed from ISO C11 and ISO C++14. Note: for
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compatibility with various implementations of <cstdio>, this test
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must consider only the value of __cplusplus when compiling C++. */
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#if defined __cplusplus ? __cplusplus >= 201402L : defined __USE_ISOC11
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# define __GLIBC_USE_DEPRECATED_GETS 0
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#else
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# define __GLIBC_USE_DEPRECATED_GETS 1
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#endif
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/* Get definitions of __STDC_* predefined macros, if the compiler has
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not preincluded this header automatically. */
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#include <stdc-predef.h>
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/* This macro indicates that the installed library is the GNU C Library.
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For historic reasons the value now is 6 and this will stay from now
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on. The use of this variable is deprecated. Use __GLIBC__ and
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__GLIBC_MINOR__ now (see below) when you want to test for a specific
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GNU C library version and use the values in <gnu/lib-names.h> to get
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the sonames of the shared libraries. */
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#undef __GNU_LIBRARY__
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#define __GNU_LIBRARY__ 6
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/* Major and minor version number of the GNU C library package. Use
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these macros to test for features in specific releases. */
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#define __GLIBC__ 2
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#define __GLIBC_MINOR__ 26
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#define __GLIBC_PREREQ(maj, min) \
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((__GLIBC__ << 16) + __GLIBC_MINOR__ >= ((maj) << 16) + (min))
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/* This is here only because every header file already includes this one. */
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#ifndef __ASSEMBLER__
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# ifndef _SYS_CDEFS_H
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# include <sys/cdefs.h>
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# endif
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/* If we don't have __REDIRECT, prototypes will be missing if
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__USE_FILE_OFFSET64 but not __USE_LARGEFILE[64]. */
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# if defined __USE_FILE_OFFSET64 && !defined __REDIRECT
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# define __USE_LARGEFILE 1
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# define __USE_LARGEFILE64 1
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# endif
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#endif /* !ASSEMBLER */
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/* Decide whether we can define 'extern inline' functions in headers. */
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#if __GNUC_PREREQ (2, 7) && defined __OPTIMIZE__ \
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&& !defined __OPTIMIZE_SIZE__ && !defined __NO_INLINE__ \
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&& defined __extern_inline
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# define __USE_EXTERN_INLINES 1
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#endif
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/* This is here only because every header file already includes this one.
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Get the definitions of all the appropriate `__stub_FUNCTION' symbols.
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<gnu/stubs.h> contains `#define __stub_FUNCTION' when FUNCTION is a stub
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that will always return failure (and set errno to ENOSYS). */
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#include <gnu/stubs.h>
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#endif /* features.h */
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