Home | History | Annotate | Line # | Download | only in gnu-linux 
      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