(PHP 5, PHP 7 < 7.4.0)
ibase_free_event_handler — Cancels a registered event handler
$event): bool
This function causes the registered event handler specified by
event to be cancelled. The callback function will
no longer be called for the events it was registered to handle.
成功時(shí)返回 true， 或者在失敗時(shí)返回 false。