Query a PHP semaphore without blocking?

Question

Is it possible to query a semaphore created with sem_get without actually blocking like the sem_acquire function does?

Cheers, Dan.

Thanks. Not the most exciting first post in the world I'll admit! ;-) — Dan, Dec 21 '09 at 15:53

score 6 · Accepted Answer · answered Dec 21 '09 at 18:41

Unfortunately, PHP does not currently support non-blocking semaphores.

If something like this is necessary you can utilize semaphores together with shared memory to create your own non-blocking lock mechanisms.

Use a shared memory variable to mark whether or not a lock exists and then use a semaphore around operations against that variable.

score 1 · Answer 2 · answered Apr 21 '17 at 22:18

1

Starting from PHP 5.6.1, it supports the $nowait parameter for sem_acquire:

bool sem_acquire ( resource $sem_identifier [, bool $nowait = false ] )

answered Apr 21 '17 at 22:18

Maxim Masiutin

2 Answers2