php man page for inotify_queue_len

INOTIFY_QUEUE_LEN(3)							 1						      INOTIFY_QUEUE_LEN(3)

inotify_queue_len - Return a number upper than zero if there are pending events

SYNOPSIS
       int inotify_queue_len (resource	$inotify_instance)

DESCRIPTION
	This  function	allows to know if inotify_read(3) will block or not. If a number upper than zero is returned, there are pending events and
       inotify_read(3) will not block.

PARAMETERS
	      o $inotify_instance
		- Resource returned by inotify_init(3)

RETURN VALUES
	Returns a number upper than zero if there are pending events.

SEE ALSO
       inotify_init(3), stream_select(3), stream_set_blocking(3).

PHP Documentation Group 												      INOTIFY_QUEUE_LEN(3)