    sem_get (PHP 4, PHP 5, PHP 7, PHP 8)
sem_get — Get a semaphore id   Description sem_get(
 int $key,
 int $max_acquire = 1,
 int $permissions = 0666,
 bool $auto_release = true
): SysvSemaphore|false  sem_get() returns an id that can be used to access the System V semaphore with the given key.   A second call to sem_get() for the same key will return a different semaphore identifier, but both identifiers access the same underlying semaphore.   If key is 0, a new private semaphore is created for each call to sem_get().    Parameters
  key
  max_acquire
   The number of processes that can acquire the semaphore simultaneously is set to max_acquire.    permissions
   The semaphore permissions. Actually this value is set only if the process finds it is the only process currently attached to the semaphore.    auto_release
   Specifies if the semaphore should be automatically released on request shutdown.      Return Values  Returns a positive semaphore identifier on success, or false on error.    Changelog
   Version Description     8.0.0  On success, this function returns a SysvSemaphore instance now; previously, a resource was returned.    8.0.0  The type of auto_release has been changed from int to bool.       Notes 
Warning  When using sem_get() to access a semaphore created outside PHP, note that the semaphore must have been created as a set of 3 semaphores (for example, by specifying 3 as the nsems parameter when calling the C semget() function), otherwise PHP will be unable to access the semaphore.     See Also
 sem_acquire() - Acquire a semaphore sem_release() - Release a semaphore ftok() - Convert a pathname and a project identifier to a System V IPC key   


    
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