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// Support for concurrent programing -*- C++ -*-

// Copyright (C) 2003, 2004

// Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library is free

// software; you can redistribute it and/or modify it under the

// terms of the GNU General Public License as published by the

// Free Software Foundation; either version 2, or (at your option)

// any later version.

// This library 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 General Public License for more details.

// You should have received a copy of the GNU General Public License along

// with this library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// USA.

// As a special exception, you may use this file as part of a free software

// library without restriction.  Specifically, if other files instantiate

// templates or use macros or inline functions from this file, or you compile

// this file and link it with other files to produce an executable, this

// file does not by itself cause the resulting executable to be covered by

// the GNU General Public License.  This exception does not however

// invalidate any other reasons why the executable file might be covered by

// the GNU General Public License.

/** @file concurrence.h

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _CONCURRENCE_H

#define _CONCURRENCE_H 1

// GCC's thread abstraction layer

#include "bits/gthr.h"

#if __GTHREADS

# ifdef __GTHREAD_MUTEX_INIT

#  define __glibcxx_mutex_type __gthread_mutex_t

#  define __glibcxx_mutex_define_initialized(NAME) \

__gthread_mutex_t NAME = __GTHREAD_MUTEX_INIT

#  define __glibcxx_mutex_lock(NAME) \

__gthread_mutex_lock(&NAME)

# else

// Implies __GTHREAD_MUTEX_INIT_FUNCTION

struct __glibcxx_mutex : public __gthread_mutex_t

{

   __glibcxx_mutex() { __GTHREAD_MUTEX_INIT_FUNCTION(this); }

};

#  define __glibcxx_mutex_type __glibcxx_mutex

#  define __glibcxx_mutex_define_initialized(NAME) \

__glibcxx_mutex NAME

# define __glibcxx_mutex_lock(NAME) \

__gthread_mutex_lock(&NAME)

# endif

# define __glibcxx_mutex_unlock(NAME) __gthread_mutex_unlock(&NAME)

#else

# define __glibcxx_mutex_type __gthread_mutex_t

# define __glibcxx_mutex_define_initialized(NAME) __gthread_mutex_t NAME

# define __glibcxx_mutex_lock(NAME)

# define __glibcxx_mutex_unlock(NAME)

#endif

namespace __gnu_cxx

{

  typedef __glibcxx_mutex_type mutex_type;

  /// @brief  Scoped lock idiom.

  // Acquire the mutex here with a constructor call, then release with

  // the destructor call in accordance with RAII style.

  class lock

  {

    // Externally defined and initialized.

    mutex_type& device;

  public:

    explicit lock(mutex_type& name) : device(name)

    { __glibcxx_mutex_lock(device); }

    ~lock() throw()

    { __glibcxx_mutex_unlock(device); }

  private:

    lock(const lock&);

    lock& operator=(const lock&);

  };

}

#endif