C++ 11实现信号量

/************************************/
/* 文件名：CSemaphore.h		    */
/* 功  能：C++11信号量		    */
/************************************/

#ifndef _CSEMAPHORE_H_
#define _CSEMAPHORE_H_

#include <mutex>
#include <condition_variable>

class CSemaphore
{
public:
	CSemaphore(long count = 0);
	void Signal();
	void Wait();

private:
	std::mutex _mutex;
	std::condition_variable _cv;
	long m_count;
};

#endif /*_CSEMAPHORE_H_*/

 

/************************************/
/* 文件名：CSemaphore.cpp	    */
/* 功  能：C++11信号量		    */
/************************************/
#include "CSemaphore.h"

CSemaphore::CSemaphore(long count)
	:m_count(count)
{
}

void CSemaphore::Signal()
{
	std::unique_lock<std::mutex> lock(_mutex);
	++m_count;
	_cv.notify_one();
}

void CSemaphore::Wait()
{
	std::unique_lock<std::mutex> lock(_mutex);
	_cv.wait(lock, [=] {return m_count > 0; });
	--m_count;
}

/* 信号量使用示例 */
#include "CSemaphore.h"
#include <iostream>

const int BufferSize = 128;
const int DataSize = 500;

int buff[BufferSize];
CSemaphore freeSpace(BufferSize);//写入线程
CSemaphore usedSpace(-100);//消费线程

std::mutex m;

void producer()
{
	for (int i = 0; i < DataSize; i++)
	{
		freeSpace.Wait();

		std::thread::id thread_id = std::this_thread::get_id();
		buff[i%BufferSize] = i;
		printf("Thread %d，生产 %d\n", thread_id, i);

		usedSpace.Signal();
		Sleep(50);
	}
}

void consumer()
{
	for (int i = 0; i < DataSize; i++)
	{
		usedSpace.Wait();

		std::thread::id thread_id = std::this_thread::get_id();
		printf("Thread %d，消费的数字 %d\n", thread_id, buff[i%BufferSize]);

		freeSpace.Signal();
	}
}

int main()
{
	std::thread threads1(producer);
	std::thread threads2(consumer);

	threads1.join();
	threads2.join();
	std::cout << "完成!" << std::endl;

	std::cin.get();
	return 0;
}