Returns: TRUE on
success, FALSE on error.
sem_remove() removes the
semaphore sem_identifier if
it has been created by sem_get(), otherwise generates a
warning.
After removing the semaphore, it is no more
accessible.
See also: sem_get(),
sem_release() and
sem_acquire().
注: This function does not work on Windows systems. It was added on PHP 4.1.0.