Query a PHP semaphore without blocking?

Question

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

Cheers, Dan.

Answer 1

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.