1/* Handle feature test macros at the start of a header.
2 Copyright (C) 2016-2024 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
111