| 1 | /* $NetBSD: featuretest.h,v 1.13 2024/09/09 15:05:39 riastradh Exp $ */ |
| 2 | |
| 3 | /* |
| 4 | * Written by Klaus Klein <kleink@NetBSD.org>, February 2, 1998. |
| 5 | * Public domain. |
| 6 | * |
| 7 | * NOTE: Do not protect this header against multiple inclusion. Doing |
| 8 | * so can have subtle side-effects due to header file inclusion order |
| 9 | * and testing of e.g. _POSIX_SOURCE vs. _POSIX_C_SOURCE. Instead, |
| 10 | * protect each CPP macro that we want to supply. |
| 11 | */ |
| 12 | |
| 13 | /* |
| 14 | * Feature-test macros are defined by several standards, and allow an |
| 15 | * application to specify what symbols they want the system headers to |
| 16 | * expose, and hence what standard they want them to conform to. |
| 17 | * There are two classes of feature-test macros. The first class |
| 18 | * specify complete standards, and if one of these is defined, header |
| 19 | * files will try to conform to the relevant standard. They are: |
| 20 | * |
| 21 | * ANSI macros: |
| 22 | * _ANSI_SOURCE ANSI C89 |
| 23 | * |
| 24 | * POSIX macros: |
| 25 | * _POSIX_SOURCE == 1 IEEE Std 1003.1 (version?) |
| 26 | * _POSIX_C_SOURCE == 1 IEEE Std 1003.1-1990 |
| 27 | * _POSIX_C_SOURCE == 2 IEEE Std 1003.2-1992 |
| 28 | * _POSIX_C_SOURCE == 199309L IEEE Std 1003.1b-1993 |
| 29 | * _POSIX_C_SOURCE == 199506L ISO/IEC 9945-1:1996 |
| 30 | * _POSIX_C_SOURCE == 200112L IEEE Std 1003.1-2001 |
| 31 | * _POSIX_C_SOURCE == 200809L IEEE Std 1003.1-2008 |
| 32 | * _POSIX_C_SOURCE == 202405L IEEE Std 1003.1-2024 |
| 33 | * |
| 34 | * Reference: |
| 35 | * |
| 36 | * The Open Group Base Specifications Issue 8, IEEE Std |
| 37 | * 1003.1-2024, IEEE and The Open Group, 2024, Sec. 2.2.1.1 `The |
| 38 | * _POSIX_C_SOURCE Feature Test Macro'. |
| 39 | * https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/V2_chap02.html#tag_16_02_01_01 |
| 40 | * |
| 41 | * X/Open macros: |
| 42 | * _XOPEN_SOURCE System Interfaces and Headers, Issue 4, Ver 2 |
| 43 | * _XOPEN_SOURCE_EXTENDED == 1 XSH4.2 UNIX extensions |
| 44 | * _XOPEN_SOURCE == 500 System Interfaces and Headers, Issue 5 |
| 45 | * _XOPEN_SOURCE == 520 Networking Services (XNS), Issue 5.2 |
| 46 | * _XOPEN_SOURCE == 600 IEEE Std 1003.1-2001, XSI option |
| 47 | * _XOPEN_SOURCE == 700 IEEE Std 1003.1-2008, XSI option |
| 48 | * _XOPEN_SOURCE == 800 IEEE Std 1003.1-2024, XSI option |
| 49 | * |
| 50 | * Reference: |
| 51 | * |
| 52 | * The Open Group Base Specifications Issue 8, IEEE Std |
| 53 | * 1003.1-2024, IEEE and The Open Group, 2024, Sec. 2.2.1.2 `The |
| 54 | * _XOPEN_SOURCE Feature Test Macro'. |
| 55 | * https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/V2_chap02.html#tag_16_02_01_02 |
| 56 | * |
| 57 | * NetBSD macros: |
| 58 | * _NETBSD_SOURCE == 1 Make all NetBSD features available. |
| 59 | * |
| 60 | * If more than one of these "major" feature-test macros is defined, |
| 61 | * then the set of facilities provided (and namespace used) is the |
| 62 | * union of that specified by the relevant standards, and in case of |
| 63 | * conflict, the earlier standard in the above list has precedence (so |
| 64 | * if both _POSIX_C_SOURCE and _NETBSD_SOURCE are defined, the version |
| 65 | * of rename() that's used is the POSIX one). If none of the "major" |
| 66 | * feature-test macros is defined, _NETBSD_SOURCE is assumed. |
| 67 | * |
| 68 | * There are also "minor" feature-test macros, which enable extra |
| 69 | * functionality in addition to some base standard. They should be |
| 70 | * defined along with one of the "major" macros. The "minor" macros |
| 71 | * are: |
| 72 | * |
| 73 | * _REENTRANT Some thread-safety extensions like lgamma_r(3) |
| 74 | * (mostly subsumed by _POSIX_C_SOURCE >= 199506L) |
| 75 | * _ISOC99_SOURCE C99 extensions like snprintf without -std=c99 |
| 76 | * _ISOC11_SOURCE C11 extensions like aligned_alloc without -std=c11 |
| 77 | * _ISOC23_SOURCE C23 extensions like mbrtoc8 without -std=c23 |
| 78 | * _OPENBSD_SOURCE Nonstandard OpenBSD extensions like strtonum(3) |
| 79 | * _GNU_SOURCE Nonstandard GNU extensions like feenableexcept(3) |
| 80 | */ |
| 81 | |
| 82 | #if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE) |
| 83 | #define _POSIX_C_SOURCE 1L |
| 84 | #endif |
| 85 | |
| 86 | #if !defined(_ANSI_SOURCE) && !defined(_POSIX_C_SOURCE) && \ |
| 87 | !defined(_XOPEN_SOURCE) && !defined(_NETBSD_SOURCE) |
| 88 | #define _NETBSD_SOURCE 1 |
| 89 | #endif |
| 90 | |
| 91 | #if ((_POSIX_C_SOURCE - 0) >= 199506L || (_XOPEN_SOURCE - 0) >= 500) && \ |
| 92 | !defined(_REENTRANT) |
| 93 | #define _REENTRANT |
| 94 | #endif |
| 95 | |
| 96 | /* |
| 97 | * The _XOPEN_SOURCE namespaces are supersets of corresponding |
| 98 | * _POSIX_C_SOURCE namespaces, so to keep the namespace tests in header |
| 99 | * files simpler, if _XOPEN_SOURCE is defined but _POSIX_C_SOURCE is |
| 100 | * not, define _POSIX_C_SOURCE to the corresponding value. |
| 101 | */ |
| 102 | #if defined(_XOPEN_SOURCE) && !defined(_POSIX_C_SOURCE) |
| 103 | |
| 104 | /* |
| 105 | * `[I]f _XOPEN_SOURCE is set equal to 800 and _POSIX_C_SOURCE is set |
| 106 | * equal to 202405L, the behavior is the same as if only _XOPEN_SOURCE |
| 107 | * is defined and set equal to 800. |
| 108 | * |
| 109 | * IEEE Std 1003.1-2024, 2.2.1.2 `The _XOPEN_SOURCE Feature Test Macro' |
| 110 | * https://pubs.opengroup.org/onlinepubs/9799919799.2024edition/functions/V2_chap02.html#tag_16_02_01_02 |
| 111 | */ |
| 112 | #if (_XOPEN_SOURCE - 0) == 800 |
| 113 | #define _POSIX_C_SOURCE 202405L |
| 114 | |
| 115 | /* |
| 116 | * `[I]f _XOPEN_SOURCE is set equal to 700 and _POSIX_C_SOURCE is set |
| 117 | * equal to 200809L, the behavior is the same as if only _XOPEN_SOURCE |
| 118 | * is defined and set equal to 700.' |
| 119 | * |
| 120 | * IEEE Std 1003.1-2008, 2.2.1 `POSIX.1 Symbols', subsection `The |
| 121 | * _XOPEN_SOURCE Feature Test Macro' |
| 122 | * https://pubs.opengroup.org/onlinepubs/9699919799.2018edition/functions/V2_chap02.html |
| 123 | */ |
| 124 | #elif (_XOPEN_SOURCE - 0) == 700 |
| 125 | #define _POSIX_C_SOURCE 200809L |
| 126 | |
| 127 | /* |
| 128 | * `[I]f _XOPEN_SOURCE is set equal to 600 and _POSIX_C_SOURCE is set |
| 129 | * equal to 200112L, the behavior is the same as if only _XOPEN_SOURCE |
| 130 | * is defined and set equal to 600.' |
| 131 | * |
| 132 | * IEEE Std 1003.1-2001, 2.2.1 `POSIX.1 Symbols', subsection `The |
| 133 | * _XOPEN_SOURCE Feature Test Macro' |
| 134 | * https://pubs.opengroup.org/onlinepubs/007904875/functions/xsh_chap02_02.html |
| 135 | */ |
| 136 | #elif (_XOPEN_SOURCE - 0) == 600 |
| 137 | #define _POSIX_C_SOURCE 200112L |
| 138 | |
| 139 | /* |
| 140 | * `[I]f _XOPEN_SOURCE is set equal to 500 and _POSIX_SOURCE is |
| 141 | * defined, or _POSIX_C_SOURCE is set greater than zero and less than |
| 142 | * or equal to 199506L, the behaviour is the same as if only |
| 143 | * _XOPEN_SOURCE is defined and set equal to 500.' |
| 144 | * |
| 145 | * Single UNIX Specification, Version 2, `The Compilation Environment' |
| 146 | * https://pubs.opengroup.org/onlinepubs/007908799/xsh/compilation.html |
| 147 | */ |
| 148 | #elif (_XOPEN_SOURCE - 0) == 500 |
| 149 | #define _POSIX_C_SOURCE 199506L |
| 150 | #endif |
| 151 | |
| 152 | #endif |