多线程通信——互斥量

最新推荐文章于 2022-12-05 16:37:22 发布

原创最新推荐文章于 2022-12-05 16:37:22 发布 · 697 阅读

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#通信 #多线程 #互斥量 #Mutex

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类似于临界段，互斥量能够保证对单个资源的互斥访问，互斥量包含一个使用数量、一个线程ID、一个递归计数器。

//创建互斥量

HANDLE CreateMutex(PSECURITY_ATTRIBUTES psa, BOOL fInitialOwner, PCTSTR pszName);

//获得它自己进程与现有互斥量相关的句柄

HANDLE OpenMutex(DWORD fdwAccess, OOL fInherit, PCTSTR pszName);

//使互斥量递归计数减1，减为0的时候，恢复已通知状态

ReleaseMutex(HANDLE hMutex);

线程通过WaitForSingleObject或者WaitForMultipleObjects来等待互斥量，若线程成功的获得了互斥量，那么互斥量中的线程ID将记录该线程的ID，并递归计数加1

应用举例：

DWORD WINAPI ThreadFuncMutex1(PVOID pParam)
{
	HANDLE* pMutex = (HANDLE*)pParam;
	for (int i=0; i <= 10; i++)
	{
		WaitForSingleObject(*pMutex, INFINITE);
		cout << "Thread1 output:" << i <<endl;
		ReleaseMutex(*pMutex);
	}
	return 0;
}

DWORD WINAPI ThreadFuncMutex2(PVOID pParam)
{
	HANDLE* pMutex = (HANDLE*)pParam;
	for (int i=0; i <= 10; i++)
	{
		WaitForSingleObject(*pMutex, INFINITE);
		cout << "Thread2 output:" << i <<endl;
		ReleaseMutex(*pMutex);
	}
	return 0;
}


int main()
{
	HANDLE hMutex = CreateMutex(NULL, false, L"Display Mutex");

	HANDLE tHandle1 = CreateThread(NULL, 0, ThreadFuncMutex1, &hMutex, 0, NULL);
	HANDLE tHandle2 = CreateThread(NULL, 0, ThreadFuncMutex2, &hMutex, 0, NULL);

	HANDLE handles[] = {tHandle1, tHandle2};
	WaitForMultipleObjects(2, handles, true, INFINITE);
	CloseHandle(hMutex);
        return 0;
}