/ray/src/lib/threads/tsemaphore.cc

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/*
 * lib/threads/tsemaphore.cc
 * 
 * Implementing semaphore class for thread synchronisation. 
 * 
 * Copyright (c) 2004 by Wolfgang Wieser ] wwieser (a) gmx <*> de [ 
 * 
 * This file may be distributed and/or modified under the terms of the 
 * GNU General Public License version 2 as published by the Free Software 
 * Foundation. (See COPYING.GPL for details.)
 * 
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 * 
 */

#include "tsemaphore.h"


#if !USE_PRIVATE__POSIX_SEMAPHORES
void Semaphore::post()
{
    m.lock();
    ++v;
    c.broadcast();
    m.unlock();
}
#endif


#if !USE_PRIVATE__POSIX_SEMAPHORES
void Semaphore::wait()
{
    m.lock();
    if(v)
    {
        --v;
        m.unlock();
        return;
    }
    // v=0; Need to wait. 
    
    // We do NOT unlock here; the condition takes care of it. 
    while(!v)  c.wait(m);
    
    m.unlock();
}
#endif


#if !USE_PRIVATE__POSIX_SEMAPHORES
bool Semaphore::test()
{
    bool retval;
    m.lock();
    if(v)
    {  --v;  retval=0;  }
    else
    {  retval=1;  }
    m.unlock();
    return(retval);
}
#endif

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