dispatch_semaphore_wait

Declaration

extern intptr_t dispatch_semaphore_wait(dispatch_semaphore_t dsema, dispatch_time_t timeout);

Parameters

• dsema:

  The semaphore. This parameter cannot be NULL.

• timeout:

  When to timeout (see Dispatch_time). The constants Dispatch_time_now and Dispatch_time_forever are available as a convenience.

Return Value

Returns zero on success, or non-zero if the timeout occurred.

Discussion

Decrement the counting semaphore. If the resulting value is less than zero, this function waits for a signal to occur before returning.