1// Specific definitions for GNU/Linux -*- C++ -*- 2 3// Copyright (C) 2000-2022 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 isalnum, 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#if __GLIBC_PREREQ(2, 34) 65// Since glibc 2.34 all pthreads functions are usable without linking to 66// libpthread. 67# define _GLIBCXX_GTHREAD_USE_WEAK 0 68#endif 69 70#endif 71