php man page for evprepare

EVPREPARE(3)								 1							      EVPREPARE(3)

The EvPrepare class

INTRODUCTION
       EvPrepare and EvCheck watchers are usually used in pairs. EvPrepare watchers get invoked before the process blocks, EvCheck afterwards.

	It  is	not allowed to call EvLoop::run or similar methods or functions that enter the current event loop from either EvPrepare or EvCheck
       watchers. Other loops than the current one are fine, however. The rationale behind this is that one don't need to check	for  recursion	in
       those  watchers,  i.e. the sequence will always be: EvPrepare -> blocking -> EvCheck , so having a watcher of each kind they will always be
       called in pairs bracketing the blocking call.

	The main purpose is to integrate other event mechanisms into libev and their use is somewhat advanced. They could be used, for example, to
       track variable changes, implement custom watchers, integrate net-snmp or a coroutine library and lots more. They are also occasionally use-
       ful to cache some data and want to flush it before blocking.

	It is recommended to give EvCheck watchers highest( Ev::MAXPRI ) priority, to ensure that they are being run  before  any  other  watchers
       after the poll (this doesn't matter for EvPrepare watchers).

	Also,  EvCheck	watchers  should  not  activate/feed events. While libev fully supports this, they might get executed before other EvCheck
       watchers did their job.

CLASS SYNOPSIS
       EvPrepare

       EvPrepareextends
       EvWatcher

       Inherited properties

       o public$is_active

       o public$data

       o public$is_pending

       o public$priority

       Methods

       o public EvPrepare::__construct (string	$callback, [string  $data], [string  $priority])

       o finalpublicstatic EvPrepare EvPrepare::createStopped NULL (callable  $callback, [mixed  $data], [int  $priority])

       Inherited methods

       o public int EvWatcher::clear (void  )

       o abstractpublic EvWatcher::__construct (void  )

       o public void EvWatcher::feed (int  $revents)

       o public EvLoop EvWatcher::getLoop (void  )

       o public void EvWatcher::invoke (int  $revents)

       o public bool EvWatcher::keepalive ([bool  $value])

       o public void EvWatcher::setCallback (callable  $callback)

       o public void EvWatcher::start (void  )

       o public void EvWatcher::stop (void  )

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