bits/libc-header-start.h

   1 /* Handle feature test macros at the start of a header.
   2    Copyright (C) 2016-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This header is internal to glibc and should not be included outside
  20    of glibc headers.  Headers including it must define
  21    __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION first.  This header
  22    cannot have multiple include guards because ISO C feature test
  23    macros depend on the definition of the macro when an affected
  24    header is included, not when the first system header is
  25    included.  */
  26
  27 #ifndef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
  28 # error "Never include <bits/libc-header-start.h> directly."
  29 #endif
  30
  31 #undef __GLIBC_INTERNAL_STARTING_HEADER_IMPLEMENTATION
  32
  33 #include <features.h>
  34
  35 /* ISO/IEC TR 24731-2:2010 defines the __STDC_WANT_LIB_EXT2__
  36    macro.  */
  37 #undef __GLIBC_USE_LIB_EXT2
  38 #if (defined __USE_GNU                                                  \
  39      || (defined __STDC_WANT_LIB_EXT2__ && __STDC_WANT_LIB_EXT2__ > 0))
  40 # define __GLIBC_USE_LIB_EXT2 1
  41 #else
  42 # define __GLIBC_USE_LIB_EXT2 0
  43 #endif
  44
  45 /* ISO/IEC TS 18661-1:2014 defines the __STDC_WANT_IEC_60559_BFP_EXT__
  46    macro.  Most but not all symbols enabled by that macro in TS
  47    18661-1 are enabled unconditionally in C2X; the symbols in Annex F
  48    still require that macro in C2X.  */
  49 #undef __GLIBC_USE_IEC_60559_BFP_EXT
  50 #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_BFP_EXT__
  51 # define __GLIBC_USE_IEC_60559_BFP_EXT 1
  52 #else
  53 # define __GLIBC_USE_IEC_60559_BFP_EXT 0
  54 #endif
  55 #undef __GLIBC_USE_IEC_60559_BFP_EXT_C2X
  56 #if __GLIBC_USE (IEC_60559_BFP_EXT) || __GLIBC_USE (ISOC2X)
  57 # define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 1
  58 #else
  59 # define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 0
  60 #endif
  61
  62 /* ISO/IEC TS 18661-4:2015 defines the
  63    __STDC_WANT_IEC_60559_FUNCS_EXT__ macro.  Other than the reduction
  64    functions, the symbols from this TS are enabled unconditionally in
  65    C2X.  */
  66 #undef __GLIBC_USE_IEC_60559_FUNCS_EXT
  67 #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_FUNCS_EXT__
  68 # define __GLIBC_USE_IEC_60559_FUNCS_EXT 1
  69 #else
  70 # define __GLIBC_USE_IEC_60559_FUNCS_EXT 0
  71 #endif
  72 #undef __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X
  73 #if __GLIBC_USE (IEC_60559_FUNCS_EXT) || __GLIBC_USE (ISOC2X)
  74 # define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 1
  75 #else
  76 # define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 0
  77 #endif
  78
  79 /* ISO/IEC TS 18661-3:2015 defines the
  80    __STDC_WANT_IEC_60559_TYPES_EXT__ macro.  */
  81 #undef __GLIBC_USE_IEC_60559_TYPES_EXT
  82 #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_TYPES_EXT__
  83 # define __GLIBC_USE_IEC_60559_TYPES_EXT 1
  84 #else
  85 # define __GLIBC_USE_IEC_60559_TYPES_EXT 0
  86 #endif