sem_remove()

(PHP 4 >= 4.1.0, PHP 5, PHP 7)

Remove a semaphore

说明

sem_remove(resource $sem_identifier): bool

sem_remove() removes the given semaphore.

After removing the semaphore, it is no longer accessible.

参数

$sem_identifier

A semaphore resource identifier as returned by sem_get().

返回值

成功时返回TRUE，或者在失败时返回FALSE。

参见

• sem_get()Get a semaphore id
• sem_release()Release a semaphore
• sem_acquire()Acquire a semaphore

sem_remove() shouldn't be part of a normal cleanup/teardown and should be called very rarely due to bugs in the implementation.
It doesn't seem to hurt to leave semaphores lying around and is likely to be more performance-friendly to do so. If you are concerned about having too many semaphores floating around for an application (e.g. a file cache that uses ftok()), you can use some modulus arithmetic and simple addition to create a limited range of values for your semaphores off in the middle of nowhere. For example, ftok() % 101 + 0xBADBEEF. Be sure to replace 0xBADBEEF with your own random value. The example limits the range to 101 semaphores. 101 is a prime number - so if you want more or less, be sure to replace it with a prime number since primes theoretically help distribute values more evenly.