src_corelib_kernel_qsystemsemaphore.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
 
#include <QSystemSemaphore>
 
void example()
{
    {
        //! [0]
        QSystemSemaphore sem(QSystemSemaphore::platformSafeKey("market"), 3, QSystemSemaphore::Create);
                                     // resources available == 3
        sem.acquire();               // resources available == 2
        sem.acquire();               // resources available == 1
        sem.acquire();               // resources available == 0
        sem.release();               // resources available == 1
        sem.release(2);              // resources available == 3
        //! [0]
    }
 
    {
        //! [1]
        QSystemSemaphore sem(QSystemSemaphore::platformSafeKey("market"), 5, QSystemSemaphore::Create);
        for (int i = 0; i < 5; ++i)  // acquire all 5 resources
            sem.acquire();
        sem.release(5);              // release the 5 resources
        //! [1]
    }
 
    {
        QSystemSemaphore sem(QSystemSemaphore::platformSafeKey("market"), 0, QSystemSemaphore::Create);
 
        //! [2]
        sem.release(10);          // "create" 10 new resources
        //! [2]
    }
}