windows 之互斥量----mutex

CreateMutexA

CreateMutexExA

CreateMutexExW

CreateMutexW

可以用互斥量作为单实例应用控制，

如：

进程A创建互斥量Mutex，

启动进程B创建互斥量Mutex失败，这时候就不打开进程B而是打开进程A

HANDLE hMutex = ::CreateMutexW(NULL, FALSE, ptr);
if (hMutex == NULL)
{
　　std::cout << "create mutex error with." << GetLastError() << std::endl;
}
else {
　　std::cout << "create mutex successful." << std::endl;
}
if (ERROR_ALREADY_EXISTS == GetLastError())
{
　　cout << "mutex has exists" << endl;
}
else
{
　　cout << "create new muetex" << endl;
}

//记得创建完后释放互斥量.

CloseHandle(hMutex);