C Pthreads 互斥值？

Question

我正在编写一个包含几个关键部分的程序。问题是我需要在 if 语句中检查互斥锁的值。

我想做这样的事情:

if pthread_mutex(&mutex) == 0 // locked 
  // Do something
else if pthread_mutex(&mutex) == 1 // unlocked 
 // Do something else

这可能吗？

Answer 1

你想要pthread_mutex_trylock() .

来自该链接:

The pthread_mutex_trylock() function shall be equivalent to pthread_mutex_lock(), except that if the mutex object referenced by mutex is currently locked (by any thread, including the current thread), the call shall return immediately. ... Return values ... The pthread_mutex_trylock() function shall return zero if a lock on the mutex object referenced by mutex is acquired. Otherwise, an error number is returned to indicate the error

所以你的代码应该是这样的:

pthread_mutex_t *m = /* ... */;

if (pthread_mutex_trylock(m) == 0)
{
    /* Success!  This thread now owns the lock. */
}
else
{
    /* Fail!  This thread doesn't own the lock.  Do something else... */
}