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glibc/bits/libc-header-start.h

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Support __STDC_WANT_LIB_EXT2__ feature test macro. This patch implements support for the __STDC_WANT_LIB_EXT2__ feature test macro from ISO/IEC TR 24731-2:2010, thereby implementing one possible approach for supporting ISO C feature test macros. Recall that, as described in <https://sourceware.org/ml/libc-alpha/2016-05/msg00486.html>, these macros work based on the definition when affected headers are included, so cannot be handled once when the first system header is included because that might not be one of the headers the particular macro in question affects. <https://sourceware.org/ml/libc-alpha/2016-05/msg00680.html> expresses views on possible approaches for implementation and <https://sourceware.org/ml/libc-alpha/2016-06/msg00039.html> follows up on that. This patch arranges things so that the relevant condition is __GLIBC_USE (LIB_EXT2), following one of the suggestions given. Headers using these macros include <bits/libc-header-start.h>, which in turn includes <features.h>. Headers must define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION before including <bits/libc-header-start.h>, to discourage inclusion outside glibc as requested. __USE_GNU conditions on affected functions are changed to __GLIBC_USE (LIB_EXT2), while it's added as an additional alternative on the conditions for functions already enabled for some POSIX versions. It would be possible to convert existing __USE_* conditionals to __GLIBC_USE (with the relevant __GLIBC_USE_* being defined in <features.h> where __USE_* are presently defined), and so make them typo-proof (given -Wundef -Werror in glibc builds) because __GLIBC_USE is used with #if not #ifdef / #if defined. No attempt is made to enforce the rule about diagnosing different definitions of __STDC_WANT_LIB_EXT2__ when affected headers are included; such a diagnostic is incompatible with multiple-include guards on the affected headers, unless compiler extensions are added to support it. As previously noted, glibc does not implement all features from TR 24731-2:2010: the functions aswprintf vaswprintf getwdelim getwline are not in glibc, although they would be appropriate to add if someone wished to do so. But I think it makes sense to support the feature test macro if *any* of the controlled features are present in glibc. Tested for x86_64 and x86 (testsuite, and that installed stripped shared libraries are unchanged by the patch). * bits/libc-header-start.h: New file. * Makefile (headers): Add bits/libc-header-start.h. * include/features.h (__STDC_WANT_LIB_EXT2__): Document. (__GLIBC_USE): New macro. * libio/stdio.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (fmemopen): Declare also if [__GLIBC_USE (LIB_EXT2)]. (open_memstream): Likewise. (vasprintf): Declare if [__GLIBC_USE (LIB_EXT2)], not [__USE_GNU]. (__asprintf): Likewise. (asprintf): Likewise. (__getdelim): Declare also if [__GLIBC_USE (LIB_EXT2)]. (getdelim): Likewise. (getline): Likewise. * string/string.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (strdup): Declare also if [__GLIBC_USE (LIB_EXT2)] (strndup): Likewise. * wcsmbs/wchar.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (open_wmemstream): Declare also if [__GLIBC_USE (LIB_EXT2)]. * manual/creature.texi (__STDC_WANT_LIB_EXT2__): Document macro.
2016-08-02 19:40:35 +02:00
/* Handle feature test macros at the start of a header.
Update copyright dates with scripts/update-copyrights. * All files with FSF copyright notices: Update copyright dates using scripts/update-copyrights. * locale/programs/charmap-kw.h: Regenerated. * locale/programs/locfile-kw.h: Likewise.
2018-01-01 01:32:25 +01:00
Copyright (C) 2016-2018 Free Software Foundation, Inc.
Support __STDC_WANT_LIB_EXT2__ feature test macro. This patch implements support for the __STDC_WANT_LIB_EXT2__ feature test macro from ISO/IEC TR 24731-2:2010, thereby implementing one possible approach for supporting ISO C feature test macros. Recall that, as described in <https://sourceware.org/ml/libc-alpha/2016-05/msg00486.html>, these macros work based on the definition when affected headers are included, so cannot be handled once when the first system header is included because that might not be one of the headers the particular macro in question affects. <https://sourceware.org/ml/libc-alpha/2016-05/msg00680.html> expresses views on possible approaches for implementation and <https://sourceware.org/ml/libc-alpha/2016-06/msg00039.html> follows up on that. This patch arranges things so that the relevant condition is __GLIBC_USE (LIB_EXT2), following one of the suggestions given. Headers using these macros include <bits/libc-header-start.h>, which in turn includes <features.h>. Headers must define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION before including <bits/libc-header-start.h>, to discourage inclusion outside glibc as requested. __USE_GNU conditions on affected functions are changed to __GLIBC_USE (LIB_EXT2), while it's added as an additional alternative on the conditions for functions already enabled for some POSIX versions. It would be possible to convert existing __USE_* conditionals to __GLIBC_USE (with the relevant __GLIBC_USE_* being defined in <features.h> where __USE_* are presently defined), and so make them typo-proof (given -Wundef -Werror in glibc builds) because __GLIBC_USE is used with #if not #ifdef / #if defined. No attempt is made to enforce the rule about diagnosing different definitions of __STDC_WANT_LIB_EXT2__ when affected headers are included; such a diagnostic is incompatible with multiple-include guards on the affected headers, unless compiler extensions are added to support it. As previously noted, glibc does not implement all features from TR 24731-2:2010: the functions aswprintf vaswprintf getwdelim getwline are not in glibc, although they would be appropriate to add if someone wished to do so. But I think it makes sense to support the feature test macro if *any* of the controlled features are present in glibc. Tested for x86_64 and x86 (testsuite, and that installed stripped shared libraries are unchanged by the patch). * bits/libc-header-start.h: New file. * Makefile (headers): Add bits/libc-header-start.h. * include/features.h (__STDC_WANT_LIB_EXT2__): Document. (__GLIBC_USE): New macro. * libio/stdio.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (fmemopen): Declare also if [__GLIBC_USE (LIB_EXT2)]. (open_memstream): Likewise. (vasprintf): Declare if [__GLIBC_USE (LIB_EXT2)], not [__USE_GNU]. (__asprintf): Likewise. (asprintf): Likewise. (__getdelim): Declare also if [__GLIBC_USE (LIB_EXT2)]. (getdelim): Likewise. (getline): Likewise. * string/string.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (strdup): Declare also if [__GLIBC_USE (LIB_EXT2)] (strndup): Likewise. * wcsmbs/wchar.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (open_wmemstream): Declare also if [__GLIBC_USE (LIB_EXT2)]. * manual/creature.texi (__STDC_WANT_LIB_EXT2__): Document macro.
2016-08-02 19:40:35 +02:00
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/>. */
/* This header is internal to glibc and should not be included outside
of glibc headers. Headers including it must define
__GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION first. This header
cannot have multiple include guards because 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. */
#ifndef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
# error "Never include <bits/libc-header-start.h> directly."
#endif
#undef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
#include <features.h>
/* ISO/IEC TR 24731-2:2010 defines the __STDC_WANT_LIB_EXT2__
macro. */
#undef __GLIBC_USE_LIB_EXT2
#if (defined __USE_GNU \
|| (defined __STDC_WANT_LIB_EXT2__ && __STDC_WANT_LIB_EXT2__ > 0))
# define __GLIBC_USE_LIB_EXT2 1
#else
# define __GLIBC_USE_LIB_EXT2 0
#endif
Support __STDC_WANT_IEC_60559_BFP_EXT__ feature test macro. This patch implements support for the __STDC_WANT_IEC_60559_BFP_EXT__ feature test macro from ISO/IEC 18661-1:2014, following the __GLIBC_USE approach now used for __STDC_WANT_LIB_EXT2__. For this macro, the relevant consideration is whether it is defined or undefined when an affected header is included (not what its value is if defined, and not whether it's defined or undefined when any other unaffected system header is included). Currently this macro only affects the issignaling macro and the nextup and nextdown functions (so they can be enabled by defining this macro, not just by defining _GNU_SOURCE as previously). Any further features from this TS added in future would also be conditioned on this macro. Tested for x86_64 and x86 (testsuite, and that installed stripped shared libraries are unchanged by the patch). * bits/libc-header-start.h (__GLIBC_USE_IEC_60559_BFP_EXT): New macro. * include/features.h (__STDC_WANT_IEC_60559_BFP_EXT__): Document. * manual/arith.texi (issignaling): Document as ISO from TS 18661-1:2014. (nextup): Likewise. (nextupf): Likewise. (nextupl): Likewise. (nextdown): Likewise. (nextdownf): Likewise. (nextdownl): Likewise. * manual/creature.texi (__STDC_WANT_IEC_60559_BFP_EXT__): Document macro. * math/math.h: Define __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION and include <bits/libc-header-start.h> instead of including <features.h>. (issignaling): Define if [__GLIBC_USE (IEC_60559_BFP_EXT)], not [__USE_GNU]. * math/bits/mathcalls.h (nextdown): Declare if [__GLIBC_USE (IEC_60559_BFP_EXT)], not [__USE_GNU]. (nextup): Likewise. (__issignaling): Likewise.
2016-08-03 19:30:41 +02:00
/* ISO/IEC TS 18661-1:2014 defines the __STDC_WANT_IEC_60559_BFP_EXT__
macro. */
#undef __GLIBC_USE_IEC_60559_BFP_EXT
#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_BFP_EXT__
# define __GLIBC_USE_IEC_60559_BFP_EXT 1
#else
# define __GLIBC_USE_IEC_60559_BFP_EXT 0
#endif
Support __STDC_WANT_IEC_60559_FUNCS_EXT__ feature test macro. This patch implements support for the __STDC_WANT_IEC_60559_FUNCS_EXT__ feature test macro, following the __GLIBC_USE approach used for other ISO C feature test macros. Currently this only affects the exp10 functions (which glibc has had for a long time). Tested for x86_64 and x86 (testsuite, and that installed stripped shared libraries are unchanged by the patch). * bits/libc-header-start.h (__GLIBC_USE_IEC_60559_FUNCS_EXT): New macro. * include/features.h (__STDC_WANT_IEC_60559_FUNCS_EXT__): Document. * manual/creature.texi (__STDC_WANT_IEC_60559_FUNCS_EXT__): Document macro. * manual/math.texi (exp10): Document as ISO from TS 18661-4:2015. (exp10f): Likewise. (exp10l): Likewise. * math/bits/mathcalls.h (exp10): Declare if [__GLIBC_USE (IEC_60559_FUNCS_EXT)], not [__USE_GNU].
2016-08-04 00:21:37 +02:00
/* ISO/IEC TS 18661-4:2015 defines the
__STDC_WANT_IEC_60559_FUNCS_EXT__ macro. */
#undef __GLIBC_USE_IEC_60559_FUNCS_EXT
#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_FUNCS_EXT__
# define __GLIBC_USE_IEC_60559_FUNCS_EXT 1
#else
# define __GLIBC_USE_IEC_60559_FUNCS_EXT 0
#endif
Add support for testing __STDC_WANT_IEC_60559_TYPES_EXT__ This macro is defined by TS 18661-3 for supporting the _FloatN and _FloatNx types, as well as the functions suffixed with fN. * bits/libc-header-start.h: (__GLIBC_USE_IEC_60559_TYPES_EXT): New macro. * include/features.h: Describe __STDC_WANT_IEC_60559_TYPES_EXT__. * manual/creature.texi: Likewise.
2016-07-20 19:14:21 +02:00
/* ISO/IEC TS 18661-3:2015 defines the
__STDC_WANT_IEC_60559_TYPES_EXT__ macro. */
#undef __GLIBC_USE_IEC_60559_TYPES_EXT
#if defined __USE_GNU || defined __STDC_WANT_IEC_60559_TYPES_EXT__
# define __GLIBC_USE_IEC_60559_TYPES_EXT 1
#else
# define __GLIBC_USE_IEC_60559_TYPES_EXT 0
#endif