12.2 Qt5多线程：使用QWaitCondition实现生产者和消费者

#include <QCoreApplication> #include <QWaitCondition> #include <QMutex> #include <QThread> #include <stdio.h> const int DataSize = 1000; const int BufferSize = 80; int buffer[BufferSize]; QWaitCondition bufferEmpty; QWaitCondition bufferFull; QMutex mutex; //(a) int numUsedBytes = 0; //(b) int rIndex = 0; //(c) class Producer : public QThread { public: Producer(); void run(); }; Producer::Producer() { } void Producer::run() { for (int i = 0; i < DataSize; i++) //(a) { mutex.lock(); if (numUsedBytes == BufferSize) //(b) bufferEmpty.wait(&mutex); //(c) buffer[i%BufferSize] = numUsedBytes; //(d) ++numUsedBytes; //增加numUsedBytes变量 bufferFull.wakeAll(); //(e) mutex.unlock(); } } class Consumer : public QThread { public: Consumer(); void run(); }; Consumer::Consumer() { } void Consumer::run() { forever { mutex.lock(); if (numUsedBytes == 0) bufferFull.wait(&mutex); //(a) printf("%ul::[%d]=%d\n", currentThreadId(), rIndex, buffer[rIndex]); //(b) rIndex = (++rIndex)%BufferSize; //将rIndex变量循环加1 --numUsedBytes; //(c) bufferEmpty.wakeAll(); //(d) mutex.unlock(); } printf("\n"); } int main(int argc, char *argv[]) { QCoreApplication a(argc, argv); Producer producer; Consumer consumerA; Consumer consumerB; producer.start(); consumerA.start(); consumerB.start(); producer.wait(); consumerA.wait(); consumerB.wait(); return a.exec(); }