The QWaitCondition class provides a condition variable for synchronizing threads. //为同步线程提供条件变量
bool QWaitCondition::wait(QMutex *lockedMutex, unsigned long time = ULONG_MAX) Releases the lockedMutex and waits on the wait condition. //释放lockedMutex并等待条件
void QWaitCondition::wakeAll() Wakes all threads waiting on the wait condition. 激活所有等待 等待条件的thread
#include #include
const int DataSize = 100000; const int BufferSize = 4096; char buffer[BufferSize];
QWaitCondition bufferIsNotFull; QWaitCondition bufferIsNotEmpty; QMutex mutex; int usedSpace = 0;
class Producer : public QThread { public: void run(); };
void Producer::run() { for (int i = 0; i < DataSize; ++i) { mutex.lock(); while (usedSpace == BufferSize)//已经填满了缓冲区，是满的 bufferIsNotFull.wait(&mutex); //等待 bufferIsNotFull /***还有空间填充 **/ buffer[i % BufferSize] = "ACGT"[uint(std::rand()) % 4]; ++usedSpace; bufferIsNotEmpty.wakeAll();//填充了之后，缓存区是非空的，会唤醒等待bufferIsNotEmpty的线程 mutex.unlock(); } }
class Consumer : public QThread { public: void run(); };
void Consumer::run() { for (int i = 0; i < DataSize; ++i) { mutex.lock(); while (usedSpace == 0)// 缓存区没有任何数据，就是空的 bufferIsNotEmpty.wait(&mutex);//等待bufferIsNotEmpty /*** 缓存区有数据 **/ std::cerr << buffer[i % BufferSize]; --usedSpace; bufferIsNotFull.wakeAll();//消费了数据后，缓存区是非满的，会唤醒等待bufferIsNotFull的线程 mutex.unlock(); } std::cerr << std::endl; }
int main() { Producer producer; Consumer consumer; producer.start(); consumer.start(); producer.wait(); consumer.wait(); return 0; }