线程安全-互斥体

内核版的令牌

 相关函数

HANDLE CreateMutexA(
  LPSECURITY_ATTRIBUTES lpMutexAttributes,
  BOOL                  bInitialOwner,//FALSE的时候，互斥体创建出来就可以用
  LPCSTR                lpName
);

示例代码，下面是两个程序，代表两个进程，两个进程中抢同一个内核令牌

//A进程代码
int main()
{
    //创建令牌
    HANDLE g_mutex = CreateMutex(NULL,FALSE,"HEHE");
    //获取令牌
    WaitForSingleObject(g_mutex,INFINITE);
    for(int i=0;i<10;i++)
    {
        Sleep(5000);
        printf("这是A进程。。。。%d
",i);
    }
    //释放令牌
    ReleaseMutex(g_mutex);
    return 0;
}

//B进程代码
int main()
{
    //创建令牌
    HANDLE g_mutex = CreateMutex(NULL,FALSE,"HEHE");
    //获取令牌
    WaitForSingleObject(g_mutex,INFINITE);
    for(int i=0;i<10;i++)
    {
        Sleep(5000);
        printf("这是B进程。。。。%d
",i);
    }
    //释放令牌
    ReleaseMutex(g_mutex);
    return 0;
}

对于CreateMutex函数的官方说明

If the function succeeds, the return value is a handle to the newly created mutex object.
If the function fails, the return value is NULL. To get extended error information, call GetLastError.
If the mutex is a named mutex and the object existed before this function call, 
the return value is a handle to the existing object, OpenMutexa> function.

可以实现一个程序只运行一份（单开）