1  /* Handle feature test macros at the start of a header.
       2     Copyright (C) 2016-2023 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.  In C2X, the symbols in
      48     Annex F still require a new feature test macro
      49     __STDC_WANT_IEC_60559_EXT__ instead (C2X does not define
      50     __STDC_WANT_IEC_60559_BFP_EXT__), while a few features from TS
      51     18661-1 are not included in C2X (and thus should depend on
      52     __STDC_WANT_IEC_60559_BFP_EXT__ even when C2X features are
      53     enabled).
      54  
      55     __GLIBC_USE (IEC_60559_BFP_EXT) controls those features from TS
      56     18661-1 not included in C2X.
      57  
      58     __GLIBC_USE (IEC_60559_BFP_EXT_C2X) controls those features from TS
      59     18661-1 that are also included in C2X (with no feature test macro
      60     required in C2X).
      61  
      62     __GLIBC_USE (IEC_60559_EXT) controls those features from TS 18661-1
      63     that are included in C2X but conditional on
      64     __STDC_WANT_IEC_60559_EXT__.  (There are currently no features
      65     conditional on __STDC_WANT_IEC_60559_EXT__ that are not in TS
      66     18661-1.)  */
      67  #undef __GLIBC_USE_IEC_60559_BFP_EXT
      68  #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_BFP_EXT__
      69  # define __GLIBC_USE_IEC_60559_BFP_EXT 1
      70  #else
      71  # define __GLIBC_USE_IEC_60559_BFP_EXT 0
      72  #endif
      73  #undef __GLIBC_USE_IEC_60559_BFP_EXT_C2X
      74  #if __GLIBC_USE (IEC_60559_BFP_EXT) || __GLIBC_USE (ISOC2X)
      75  # define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 1
      76  #else
      77  # define __GLIBC_USE_IEC_60559_BFP_EXT_C2X 0
      78  #endif
      79  #undef __GLIBC_USE_IEC_60559_EXT
      80  #if __GLIBC_USE (IEC_60559_BFP_EXT) || defined __STDC_WANT_IEC_60559_EXT__
      81  # define __GLIBC_USE_IEC_60559_EXT 1
      82  #else
      83  # define __GLIBC_USE_IEC_60559_EXT 0
      84  #endif
      85  
      86  /* ISO/IEC TS 18661-4:2015 defines the
      87     __STDC_WANT_IEC_60559_FUNCS_EXT__ macro.  Other than the reduction
      88     functions, the symbols from this TS are enabled unconditionally in
      89     C2X.  */
      90  #undef __GLIBC_USE_IEC_60559_FUNCS_EXT
      91  #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_FUNCS_EXT__
      92  # define __GLIBC_USE_IEC_60559_FUNCS_EXT 1
      93  #else
      94  # define __GLIBC_USE_IEC_60559_FUNCS_EXT 0
      95  #endif
      96  #undef __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X
      97  #if __GLIBC_USE (IEC_60559_FUNCS_EXT) || __GLIBC_USE (ISOC2X)
      98  # define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 1
      99  #else
     100  # define __GLIBC_USE_IEC_60559_FUNCS_EXT_C2X 0
     101  #endif
     102  
     103  /* ISO/IEC TS 18661-3:2015 defines the
     104     __STDC_WANT_IEC_60559_TYPES_EXT__ macro.  */
     105  #undef __GLIBC_USE_IEC_60559_TYPES_EXT
     106  #if defined __USE_GNU || defined __STDC_WANT_IEC_60559_TYPES_EXT__
     107  # define __GLIBC_USE_IEC_60559_TYPES_EXT 1
     108  #else
     109  # define __GLIBC_USE_IEC_60559_TYPES_EXT 0
     110  #endif