libstdc++-v3/include/bits/concurrence.h

   1 // Support for concurrent programing -*- C++ -*-
   2
   3 // Copyright (C) 2003, 2004
   4 // Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING.  If not, write to the Free
  19 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  20 // USA.
  21
  22 // As a special exception, you may use this file as part of a free software
  23 // library without restriction.  Specifically, if other files instantiate
  24 // templates or use macros or inline functions from this file, or you compile
  25 // this file and link it with other files to produce an executable, this
  26 // file does not by itself cause the resulting executable to be covered by
  27 // the GNU General Public License.  This exception does not however
  28 // invalidate any other reasons why the executable file might be covered by
  29 // the GNU General Public License.
  30
  31 /** @file concurrence.h
  32  *  This is an internal header file, included by other library headers.
  33  *  You should not attempt to use it directly.
  34  */
  35
  36 #ifndef _CONCURRENCE_H
  37 #define _CONCURRENCE_H 1
  38
  39 // GCC's thread abstraction layer
  40 #include "bits/gthr.h"
  41
  42 #if __GTHREADS
  43
  44 # ifdef __GTHREAD_MUTEX_INIT
  45 #  define __glibcxx_mutex_type __gthread_mutex_t
  46 #  define __glibcxx_mutex_define_initialized(NAME) \
  47 __gthread_mutex_t NAME = __GTHREAD_MUTEX_INIT
  48 #  define __glibcxx_mutex_lock(NAME) \
  49 __gthread_mutex_lock(&NAME)
  50 # else
  51 // Implies __GTHREAD_MUTEX_INIT_FUNCTION
  52 struct __glibcxx_mutex : public __gthread_mutex_t
  53 {
  54    __glibcxx_mutex() { __GTHREAD_MUTEX_INIT_FUNCTION(this); }
  55 };
  56
  57 #  define __glibcxx_mutex_type __glibcxx_mutex
  58 #  define __glibcxx_mutex_define_initialized(NAME) \
  59 __glibcxx_mutex NAME
  60 # define __glibcxx_mutex_lock(NAME) \
  61 __gthread_mutex_lock(&NAME)
  62 # endif
  63
  64 # define __glibcxx_mutex_unlock(NAME) __gthread_mutex_unlock(&NAME)
  65
  66 #else
  67
  68 # define __glibcxx_mutex_type __gthread_mutex_t
  69 # define __glibcxx_mutex_define_initialized(NAME) __gthread_mutex_t NAME
  70 # define __glibcxx_mutex_lock(NAME)
  71 # define __glibcxx_mutex_unlock(NAME)
  72
  73 #endif
  74
  75 namespace __gnu_cxx
  76 {
  77   typedef __glibcxx_mutex_type mutex_type;
  78
  79   /// @brief  Scoped lock idiom.
  80   // Acquire the mutex here with a constructor call, then release with
  81   // the destructor call in accordance with RAII style.
  82   class lock
  83   {
  84     // Externally defined and initialized.
  85     mutex_type& device;
  86
  87   public:
  88     explicit lock(mutex_type& name) : device(name)
  89     { __glibcxx_mutex_lock(device); }
  90
  91     ~lock() throw()
  92     { __glibcxx_mutex_unlock(device); }
  93
  94   private:
  95     lock(const lock&);
  96     lock& operator=(const lock&);
  97   };
  98 }
  99
 100 #endif