kc3-lang/gnulib/lib/thread-optim.h

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• Hash : 45122e72
  Author :
  Date : 2023-04-13T23:48:40
  

  Add more reminders to include <config.h>.
  
  * lib/aligned-malloc.h: Check that config.h was already included.
  * lib/careadlinkat.h: Likewise.
  * lib/filemode.h: Likewise.
  * lib/freadptr.h: Likewise.
  * lib/fseterr.h: Likewise.
  * lib/glthread/lock.h: Likewise.
  * lib/glthread/tls.h: Likewise.
  * lib/immutable.h: Likewise.
  * lib/isapipe.h: Likewise.
  * lib/isnand-nolibm.h: Likewise.
  * lib/isnanf-nolibm.h: Likewise.
  * lib/isnanl-nolibm.h: Likewise.
  * lib/mbswidth.h: Likewise.
  * lib/md5.h: Likewise.
  * lib/minmax.h: Likewise.
  * lib/msvc-inval.h: Likewise.
  * lib/msvc-nothrow.h: Likewise.
  * lib/pathmax.h: Likewise.
  * lib/sha1.h: Likewise.
  * lib/sha256.h: Likewise.
  * lib/sha512.h: Likewise.
  * lib/size_max.h: Likewise.
  * lib/sm3.h: Likewise.
  * lib/stat-size.h: Likewise.
  * lib/termcap.h: Likewise.
  * lib/terminfo.h: Likewise.
  * lib/thread-optim.h: Likewise.
  * lib/unlocked-io.h: Likewise.
  * lib/vma-iter.h: Likewise.
  

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• lib/thread-optim.h

• /* Optimization of multithreaded code.
  
     Copyright (C) 2020-2023 Free Software Foundation, Inc.
  
     This file is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as
     published by the Free Software Foundation; either version 2.1 of the
     License, or (at your option) any later version.
  
     This file is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public License
     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  
  /* Written by Bruno Haible <bruno@clisp.org>, 2020.  */
  
  #ifndef _THREAD_OPTIM_H
  #define _THREAD_OPTIM_H
  
  /* This file defines a way to optimize multithreaded code for the single-thread
     case, based on the variable '__libc_single_threaded', defined in
     glibc >= 2.32.  */
  
  /* Typical use: In a block or function, use
  
       bool mt = gl_multithreaded ();
       ...
       if (mt)
         if (pthread_mutex_lock (&lock)) abort ();
       ...
       if (mt)
         if (pthread_mutex_unlock (&lock)) abort ();
  
     The gl_multithreaded () invocation determines whether the program currently
     is multithreaded.
  
     if (mt) STATEMENT executes STATEMENT in the multithreaded case, and skips
     it in the single-threaded case.
  
     The code between the gl_multithreaded () invocation and any use of the
     variable 'mt' must not create threads or invoke functions that may
     indirectly create threads (e.g. 'dlopen' may, indirectly through C++
     initializers of global variables in the shared library being opened,
     create threads).
  
     The lock here is meant to synchronize threads in the same process.  The
     same optimization cannot be applied to locks that synchronize different
     processes (e.g. through shared memory mappings).  */
  
  /* This file uses HAVE_SYS_SINGLE_THREADED_H.  */
  #if !_GL_CONFIG_H_INCLUDED
   #error "Please include config.h first."
  #endif
  
  #if HAVE_SYS_SINGLE_THREADED_H /* glibc >= 2.32 */
  # include <sys/single_threaded.h>
  # define gl_multithreaded()  (!__libc_single_threaded)
  #else
  # define gl_multithreaded()  1
  #endif
  
  #endif /* _THREAD_OPTIM_H */
  

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