sem_remove

(PHP 4 >= 4.1.0, PHP 5, PHP 7, PHP 8)

sem_remove — Remove a semaphore

说明

sem_remove(SysvSemaphore $semaphore): bool

sem_remove() removes the given semaphore.

After removing the semaphore, it is no longer accessible.

参数

semaphore: A semaphore as returned by sem_get().

返回值

成功时返回 true，或者在失败时返回 false。

更新日志

版本	说明
8.0.0	`semaphore` expects a SysvSemaphore instance now; previously, a resource was expected.

参见

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

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User Contributed Notes 1 note

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donotcallme at iwillcallyou dot com ¶

8 years ago


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.

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官方地址：https://www.php.net/manual/en/function.sem-remove.php

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sem_remove

说明

参数

返回值

更新日志

参见

User Contributed Notes 1 note