semaphores.cpp Example File | Qt Core 5.6

Qt 5.6 | Qt Core | Semaphores Example | semaphores.cpp Example File

Qt 5.6.2 Reference Documentation

# semaphores.cpp Example File

threads/semaphores/semaphores.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2015 The Qt Company Ltd.
      ** Contact: http://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** You may use this file under the terms of the BSD license as follows:
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      #include <QtCore>

      #include <stdio.h>
      #include <stdlib.h>

      const int DataSize = 100000;

      const int BufferSize = 8192;
      char buffer[BufferSize];

      QSemaphore freeBytes(BufferSize);
      QSemaphore usedBytes;

      class Producer : public QThread
      {
      public:
          void run() Q_DECL_OVERRIDE
          {
              qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
              for (int i = 0; i < DataSize; ++i) {
                  freeBytes.acquire();
                  buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
                  usedBytes.release();
              }
          }
      };

      class Consumer : public QThread
      {
          Q_OBJECT
      public:
          void run() Q_DECL_OVERRIDE
          {
              for (int i = 0; i < DataSize; ++i) {
                  usedBytes.acquire();
                  fprintf(stderr, "%c", buffer[i % BufferSize]);
                  freeBytes.release();
              }
              fprintf(stderr, "\n");
          }

      signals:
          void stringConsumed(const QString &text);

      protected:
          bool finish;
      };

      int main(int argc, char *argv[])
      {
          QCoreApplication app(argc, argv);
          Producer producer;
          Consumer consumer;
          producer.start();
          consumer.start();
          producer.wait();
          consumer.wait();
          return 0;
      }

      #include "semaphores.moc"