第单元 多线程并行编程模型.pptVIP

* Present and describe the WaitForSingleObject() routine. You can use the WaitForSingleObject() function to wait on a single thread to terminate. This function requires a HANDLE as a parameter, which can be for any kernel object, such as a thread, an event, a mutex, or a semaphore. When the input HANDLE is a thread, the thread calling the WaitForSingleObject() function will block waiting for the thread, whose HANDLE has been sent as the parameter, to terminate. HANDLES have two states, signaled and non-signaled. When a thread exits, its HANDLE becomes signaled, else it is non-signaled. The WaitForSingleObject() function will block the calling thread until the HANDLE is signaled; for threads, when the thread has terminated execution. The second parameter is the time limit to wait for the completion of the call. If this wait time expires, the function will return regardless of whether the HANDLE is signaled or not. In this instance, the return code indicates that the time expired caused the return. Microsoft defines a special constant, INFINITE, to indicate that the calling thread wants to wait indefinitely for the HANDLE to be signaled. In this way, you can notify the operating system that the calling thread has no other work to do until this particular event occurs, and therefore, it can be moved off the run queue to the wait queue. The operating system can then switch to a thread that is in the ready-to-run state. If you use a non-INFINTE value for this parameter, check the error code to determine the reason or why the function returned. WaitForSingleObject() function will return one of the following values: WAIT_OBJECT_0: The WaitForSingleObject() function returns this value when the object that is being waited on enters the signaled state. WAIT_TIMEOUT: The WaitForSingleObject() function returns this value when the specified timeout value occurs prior to the object entering the signaled state. WAIT_ABANDONED: If the HANDLE refers to a Mutex object, this