libstdc++
os_defines.h
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1 // Specific definitions for GNU/Linux -*- C++ -*-
2 
3 // Copyright (C) 2000-2020 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file bits/os_defines.h
26  * This is an internal header file, included by other library headers.
27  * Do not attempt to use it directly. @headername{iosfwd}
28  */
29 
30 #ifndef _GLIBCXX_OS_DEFINES
31 #define _GLIBCXX_OS_DEFINES 1
32 
33 // System-specific #define, typedefs, corrections, etc, go here. This
34 // file will come before all others.
35 
36 // This keeps isanum, et al from being propagated as macros.
37 #define __NO_CTYPE 1
38 
39 #include <features.h>
40 
41 // Provide a declaration for the possibly deprecated gets function, as
42 // glibc 2.15 and later does not declare gets for ISO C11 when
43 // __GNU_SOURCE is defined.
44 #if __GLIBC_PREREQ(2,15) && defined(_GNU_SOURCE)
45 # undef _GLIBCXX_HAVE_GETS
46 #endif
47 
48 // Glibc 2.23 removed the obsolete isinf and isnan declarations. Check the
49 // version dynamically in case it has changed since libstdc++ was configured.
50 #define _GLIBCXX_NO_OBSOLETE_ISINF_ISNAN_DYNAMIC __GLIBC_PREREQ(2,23)
51 
52 #if __GLIBC_PREREQ(2, 27)
53 // Since glibc 2.27 pthread_self() is usable without linking to libpthread.
54 # define _GLIBCXX_NATIVE_THREAD_ID pthread_self()
55 #else
56 // Before then it was in libc.so.6 but not libc.a, and always returns 0,
57 // which breaks the invariant this_thread::get_id() != thread::id{}.
58 // So only use it if we know the libpthread version is available.
59 // Otherwise use (__gthread_t)1 as the ID of the main (and only) thread.
60 # define _GLIBCXX_NATIVE_THREAD_ID \
61  (__gthread_active_p() ? __gthread_self() : (__gthread_t)1)
62 #endif
63 
64 #endif
Defines on whether to include algorithm variants.