EVENTBASE(3) 1 EVENTBASE(3)
The EventBase class
INTRODUCTION
EventBase class represents libevent's event base structure. It holds a set of events and can poll to determine which events are active.
Each event base has a method , or a backend that it uses to determine which events are ready. The recognized methods are: select , poll ,
epoll , kqueue , devpoll , evport and win32 .
To configure event base to use, or avoid specific backend EventConfig class can be used.
Warning
Do NOT destroy the EventBase object as long as resources of the associated Event objects are not released. Otherwise, it will lead
to unpredictable results!
CLASS SYNOPSIS
EventBase
final
EventBase
Constants
o const integer$EventBase::LOOP_ONCE1
o const integer$EventBase::LOOP_NONBLOCK2
o const integer$EventBase::NOLOCK1
o const integer$EventBase::STARTUP_IOCP4
o const integer$EventBase::NO_CACHE_TIME8
o const integer$EventBase::EPOLL_USE_CHANGELIST16
Methods
o public EventBase::__construct ([EventConfig $cfg])
o public void EventBase::dispatch (void )
o public bool EventBase::exit ([double $timeout])
o public void EventBase::free (void )
o public int EventBase::getFeatures (void )
o public string EventBase::getMethod ([EventConfig $cfg])
o public double EventBase::getTimeOfDayCached (void )
o public bool EventBase::gotExit (void )
o public bool EventBase::gotStop (void )
o public bool EventBase::loop ([int $flags])
o public bool EventBase::priorityInit (int $n_priorities)
o public bool EventBase::reInit (void )
o public bool EventBase::stop (void )
PREDEFINED CONSTANTS
o EventBase::LOOP_ONCE - Flag used with EventBase::loop method which means: "block until libevent has an active event, then exit
once all active events have had their callbacks run".
o EventBase::LOOP_NONBLOCK - Flag used with EventBase::loop method which means: "do not block: see which events are ready now, run
the callbacks of the highest-priority ones, then exit".
o EventBase::NOLOCK - Configuration flag. Do not allocate a lock for the event base, even if we have locking set up".
o EventBase::STARTUP_IOCP - Windows-only configuration flag. Enables the IOCP dispatcher at startup.
o EventBase::NO_CACHE_TIME - Configuration flag. Instead of checking the current time every time the event loop is ready to run
timeout callbacks, check after each timeout callback.
o EventBase::EPOLL_USE_CHANGELIST - If we are using the epoll backend, this flag says that it is safe to use Libevent's internal
change-list code to batch up adds and deletes in order to try to do as few syscalls as possible. Setting this flag can make code
run faster, but it may trigger a Linux bug: it is not safe to use this flag if one has any fds cloned by dup(), or its variants.
Doing so will produce strange and hard-to-diagnose bugs. This flag can also be activated by settnig the EVENT_EPOLL_USE_CHANGE-
LIST environment variable. This flag has no effect if one winds up using a backend other than epoll .
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