PV.rar_pv

#include <windows.h> #include <iostream> const unsigned short size_of_buffer = 10; //缓冲区长度 unsigned short ProductID = 0; //产品号 unsigned short ConsumeID = 0; //将被消耗的产品号 unsigned short in = 0; //产品进缓冲区时的缓冲区下标 unsigned short out = 0; //产品出缓冲区时的缓冲区下标 int g_buffer[size_of_buffer]; //缓冲区是个循环队列 bool g_continue = true; //控制程序结束 HANDLE g_hMutex; //用于线程间的互斥 HANDLE g_hFullSemaphore; //当缓冲区满时迫使生产者等待 HANDLE g_hEmptySemaphore; //当缓冲区空时迫使消费者等待 DWORD WINAPI Producer(LPVOID); //生产者线程 DWORD WINAPI Consumer(LPVOID); //消费者线程 int main() { //创建各个互斥信号 g_hMutex = CreateMutex(NULL,FALSE,NULL); g_hFullSemaphore = CreateSemaphore(NULL,size_of_buffer-1,size_of_buffer-1,NULL); g_hEmptySemaphore = CreateSemaphore(NULL,0,size_of_buffer-1,NULL); //调整下面的数值，可以发现，当生产者个数多于消费者个数时，生产速度快，生产者经常等待消费者；反之，消费者经常等待 const unsigned short Produces_count = 3; //生产者的个数 const unsigned short Consumers_count = 1; //消费者的个数 //总的线程数 const unsigned short THREADS_count = Produces_count+Consumers_count; HANDLE hThreads[Produces_count]; //各线程的handle DWORD producerID[Consumers_count]; //生产者线程的标识符 DWORD consumerID[THREADS_count]; //消费者线程的标识符 //创建生产者线程 for (int i=0;i<Produces_count;++i){ hThreads[i]=CreateThread(NULL,0,Producer,NULL,0,&producerID[i]); if (hThreads[i]==NULL) return -1; } //创建消费者线程 for (int j=0;j<Consumers_count;++j){ hThreads[Produces_count+j]=CreateThread(NULL,0,Consumer,NULL,0,&consumerID[j]); if (hThreads[j]==NULL) return -1; } while(g_continue){ if(getchar()){ //按回车后终止程序运行 g_continue = false; } } return 0; } //生产一个产品。简单模拟了一下，仅输出新产品的ID号 void Produce() { std::cerr << "Producing " << ++ProductID << " ... "; std::cerr << "Succeed" << std::endl; } //把新生产的产品放入缓冲区 void Append() { std::cerr << "Appending a product ... "; g_buffer[in] = ProductID; in = (in+1)%size_of_buffer; std::cerr << "Succeed" << std::endl; //输出缓冲区当前的状态 for (int i=0;i<size_of_buffer;++i){ std::cout << i <<": " << g_buffer[i]; if (i==in) std::cout << " <-- 生产"; if (i==out) std::cout << " <-- 消费"; std::cout << std::endl; } } //从缓冲区中取出一个产品 void Take() { std::cerr << "Taking a product ... "; ConsumeID = g_buffer[out]; out = (out+1)%size_of_buffer; std::cerr << "Succeed" << std::endl; //输出缓冲区当前的状态 for (int i=0;i<size_of_buffer;++i){ std::cout << i <<": " << g_buffer[i]; if (i==in) std::cout << " <-- 生产"; if (i==out) std::cout << " <-- 消费"; std::cout << std::endl; } } //消耗一个产品 void Consume() { std::cerr << "Consuming " << ConsumeID << " ... "; std::cerr << "Succeed" << std::endl; } //生产者 DWORD WINAPI Producer(LPVOID lpPara) { while(g_continue){ WaitForSingleObject(g_hFullSemaphore,INFINITE); WaitForSingleObject(g_hMutex,INFINITE); Produce(); Append(); Sleep(1500); ReleaseMutex(g_hMutex); ReleaseSemaphore(g_hEmptySemaphore,1,NULL); } return 0; } //消费者 DWORD WINAPI Consumer(LPVOID lpPara) { while(g_continue){ WaitForSingleObject(g_hEmptySemaphore,INFINITE); WaitForSingleObject(g_hMutex,INFINITE); Take(); Consume(); Sleep(1500); ReleaseMutex(g_hMutex); ReleaseSemaphore(g_hFullSemaphore,1,NULL); } return 0; }