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.
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/* Handle feature test macros at the start of a header.
Copyright (C) 2016-2023 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.
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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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
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<https://www.gnu.org/licenses/>. */
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.
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/* 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.
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/* ISO/IEC TS 18661-1:2014 defines the __STDC_WANT_IEC_60559_BFP_EXT__
Declare most TS 18661-1 interfaces for C2X. C2X adds the interfaces from TS 18661-1, and all except a handful in Annex F are unconditionally visible in C2X rather than only visible when __STDC_WANT_IEC_60559_BFP_EXT__ is defined. This patch updates glibc headers accordingly: most uses of __GLIBC_USE (IEC_60559_BFP_EXT) are changed to a new __GLIBC_USE (IEC_60559_BFP_EXT_C2X). (Regarding totalorder and totalordermag, the type-generic macros in tgmath.h will go away when the functions are changed to take pointer arguments.) * bits/libc-header-start.h (__GLIBC_USE_IEC_60559_BFP_EXT): Update comment. (__GLIBC_USE_IEC_60559_BFP_EXT_C2X): New macro. * bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Change to [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)]. * include/limits.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/bits/stdlib-ldbl.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/stdint.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/stdlib.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/aarch64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/alpha/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/arm/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/csky/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/hppa/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/ia64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/m68k/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/microblaze/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/mips/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/nios2/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/powerpc/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/riscv/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/s390/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/sh/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/sparc/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/x86/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise, except for totalorder, totalordermag, getpayload, setpayload and setpayloadsig. * math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise, except for totalorder and totalordermag.
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macro. Most but not all symbols enabled by that macro in TS
Update floating-point feature test macro handling for C2X ISO C2X has made some changes to the handling of feature test macros related to features from the floating-point TSes, and to exactly what such features are present in what headers, that require corresponding changes in glibc. * For the few features that were controlled by __STDC_WANT_IEC_60559_BFP_EXT__ (and the corresponding DFP macro) in C2X, there is now instead a new feature test macro __STDC_WANT_IEC_60559_EXT__ covering both binary and decimal FP. This controls CR_DECIMAL_DIG in <float.h> (provided by GCC; I implemented support for the new feature test macro for GCC 11) and the totalorder and payload functions in <math.h>. C2X no longer says anything about __STDC_WANT_IEC_60559_BFP_EXT__ (so it's appropriate for that macro to continue to enable exactly the features from TS 18661-1). * The SNAN macros for each floating-point type have moved to <float.h> (and been renamed in the process). Thus, the copies in <math.h> should only be defined for __STDC_WANT_IEC_60559_BFP_EXT__, not for C2X. * The fmaxmag and fminmag functions have been removed (replaced by new functions for the new min/max operations in IEEE 754-2019). Thus those should also only be declared for __STDC_WANT_IEC_60559_BFP_EXT__. * The _FloatN / _FloatNx handling for the last two points in glibc is trickier, since __STDC_WANT_IEC_60559_TYPES_EXT__ is still in C2X (the integration of TS 18661-3 as an Annex, that is, which hasn't yet been merged into the C standard git repository but has been accepted by WG14), so C2X with that macro should not declare some things that are declared for older standards with that macro. The approach taken here is to provide the declarations (when __STDC_WANT_IEC_60559_TYPES_EXT__ is enabled) only when (defined __USE_GNU || !__GLIBC_USE (ISOC2X)), so if C2X features are enabled then those declarations (that are only in TS 18661-3 and not in C2X) will only be provided if _GNU_SOURCE is defined as well. Thus _GNU_SOURCE remains a superset of the TS features as well as of C2X. Some other somewhat related changes in C2X are not addressed here. There's an open proposal not to include the fmin and fmax functions for the _FloatN / _FloatNx types, given the new min/max operations, which could be handled like the previous point if adopted. And the fromfp functions have been changed to return a result in floating type rather than intmax_t / uintmax_t; my inclination there is to treat that like that change of totalorder type (new symbol versions etc. for the ABI change; old versions become compat symbols and are no longer supported as an API). Tested for x86_64 and x86.
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18661-1 are enabled unconditionally in C2X. In C2X, the symbols in
Annex F still require a new feature test macro
__STDC_WANT_IEC_60559_EXT__ instead (C2X does not define
__STDC_WANT_IEC_60559_BFP_EXT__), while a few features from TS
18661-1 are not included in C2X (and thus should depend on
__STDC_WANT_IEC_60559_BFP_EXT__ even when C2X features are
enabled).
__GLIBC_USE (IEC_60559_BFP_EXT) controls those features from TS
18661-1 not included in C2X.
__GLIBC_USE (IEC_60559_BFP_EXT_C2X) controls those features from TS
18661-1 that are also included in C2X (with no feature test macro
required in C2X).
__GLIBC_USE (IEC_60559_EXT) controls those features from TS 18661-1
that are included in C2X but conditional on
__STDC_WANT_IEC_60559_EXT__. (There are currently no features
conditional on __STDC_WANT_IEC_60559_EXT__ that are not in TS
18661-1.) */
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.
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#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
Declare most TS 18661-1 interfaces for C2X. C2X adds the interfaces from TS 18661-1, and all except a handful in Annex F are unconditionally visible in C2X rather than only visible when __STDC_WANT_IEC_60559_BFP_EXT__ is defined. This patch updates glibc headers accordingly: most uses of __GLIBC_USE (IEC_60559_BFP_EXT) are changed to a new __GLIBC_USE (IEC_60559_BFP_EXT_C2X). (Regarding totalorder and totalordermag, the type-generic macros in tgmath.h will go away when the functions are changed to take pointer arguments.) * bits/libc-header-start.h (__GLIBC_USE_IEC_60559_BFP_EXT): Update comment. (__GLIBC_USE_IEC_60559_BFP_EXT_C2X): New macro. * bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Change to [__GLIBC_USE (IEC_60559_BFP_EXT_C2X)]. * include/limits.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/bits/stdlib-ldbl.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/stdint.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * stdlib/stdlib.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/aarch64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/alpha/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/arm/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/csky/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/hppa/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/ia64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/m68k/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/microblaze/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/mips/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/nios2/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/powerpc/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/riscv/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/s390/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/sh/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/sparc/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * sysdeps/x86/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise. * math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise, except for totalorder, totalordermag, getpayload, setpayload and setpayloadsig. * math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Likewise, except for totalorder and totalordermag.
2019-08-13 19:28:51 +08:00
#undef __GLIBC_USE_IEC_60559_BFP_EXT_C2X
#if __GLIBC_USE (IEC_60559_BFP_EXT) || __GLIBC_USE (ISOC2X)
# define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 1
#else
# define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 0
#endif
Update floating-point feature test macro handling for C2X ISO C2X has made some changes to the handling of feature test macros related to features from the floating-point TSes, and to exactly what such features are present in what headers, that require corresponding changes in glibc. * For the few features that were controlled by __STDC_WANT_IEC_60559_BFP_EXT__ (and the corresponding DFP macro) in C2X, there is now instead a new feature test macro __STDC_WANT_IEC_60559_EXT__ covering both binary and decimal FP. This controls CR_DECIMAL_DIG in <float.h> (provided by GCC; I implemented support for the new feature test macro for GCC 11) and the totalorder and payload functions in <math.h>. C2X no longer says anything about __STDC_WANT_IEC_60559_BFP_EXT__ (so it's appropriate for that macro to continue to enable exactly the features from TS 18661-1). * The SNAN macros for each floating-point type have moved to <float.h> (and been renamed in the process). Thus, the copies in <math.h> should only be defined for __STDC_WANT_IEC_60559_BFP_EXT__, not for C2X. * The fmaxmag and fminmag functions have been removed (replaced by new functions for the new min/max operations in IEEE 754-2019). Thus those should also only be declared for __STDC_WANT_IEC_60559_BFP_EXT__. * The _FloatN / _FloatNx handling for the last two points in glibc is trickier, since __STDC_WANT_IEC_60559_TYPES_EXT__ is still in C2X (the integration of TS 18661-3 as an Annex, that is, which hasn't yet been merged into the C standard git repository but has been accepted by WG14), so C2X with that macro should not declare some things that are declared for older standards with that macro. The approach taken here is to provide the declarations (when __STDC_WANT_IEC_60559_TYPES_EXT__ is enabled) only when (defined __USE_GNU || !__GLIBC_USE (ISOC2X)), so if C2X features are enabled then those declarations (that are only in TS 18661-3 and not in C2X) will only be provided if _GNU_SOURCE is defined as well. Thus _GNU_SOURCE remains a superset of the TS features as well as of C2X. Some other somewhat related changes in C2X are not addressed here. There's an open proposal not to include the fmin and fmax functions for the _FloatN / _FloatNx types, given the new min/max operations, which could be handled like the previous point if adopted. And the fromfp functions have been changed to return a result in floating type rather than intmax_t / uintmax_t; my inclination there is to treat that like that change of totalorder type (new symbol versions etc. for the ABI change; old versions become compat symbols and are no longer supported as an API). Tested for x86_64 and x86.
2021-06-01 22:22:06 +08:00
#undef __GLIBC_USE_IEC_60559_EXT
#if __GLIBC_USE (IEC_60559_BFP_EXT) || defined __STDC_WANT_IEC_60559_EXT__
# define __GLIBC_USE_IEC_60559_EXT 1
#else
# define __GLIBC_USE_IEC_60559_EXT 0
#endif
/* ISO/IEC TS 18661-4:2015 defines the
__STDC_WANT_IEC_60559_FUNCS_EXT__ macro. Other than the reduction
functions, the symbols from this TS are enabled unconditionally in
C2X. */
#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
#undef __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X
#if __GLIBC_USE (IEC_60559_FUNCS_EXT) || __GLIBC_USE (ISOC2X)
# define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 1
#else
# define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 0
#endif
/* 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