mutex 和 semaphone 的区别 (1)

MSDN:

 

A thread that owns a mutex object can wait repeatedly for the same mutex object
to become signaled without its execution becoming blocked. A thread that waits
repeatedly for the same semaphore object, however, decrements the semaphore's
count each time a wait operation is completed; the thread is blocked when the
count gets to zero. Similarly, only the thread that owns a mutex can
successfully call the ReleaseMutex
function, though any thread can use ReleaseSemaphore to increase the count of
a semaphore object.

 

 

 

本以为数量为1的semaphone和mutex没有区别，读了上面这段说明才知道，mutex的owner线程可以无限次成功调用ReleaseMutex，而ReleaseSemaphore则不判断调用是否来自owner线程。感觉上这种设计让semaphore更符合计数器的这样一个语义。