1// Specific definitions for GNU/Linux -*- C++ -*-
2
3// Copyright (C) 2000-2021 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
65