PHP Australia Conference 2015

sem_remove

(PHP 4 >= 4.1.0, PHP 5)

sem_removeRemove a semaphore

Description

bool sem_remove ( resource $sem_identifier )

sem_remove() removes the given semaphore.

After removing the semaphore, it is no longer accessible.

Parameters

sem_identifier

A semaphore resource identifier as returned by sem_get().

Return Values

Returns TRUE on success or FALSE on failure.

See Also

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User Contributed Notes 1 note

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donotcallme at iwillcallyou dot com
11 months 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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