The EventBase class

The EventBase class

(PECL event >= 1.2.6-beta)


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.


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!


final class EventBase {
/* Constants */
const int LOOP_ONCE = 1;
const int LOOP_NONBLOCK = 2;
const int NOLOCK = 1;
const int STARTUP_IOCP = 4;
const int NO_CACHE_TIME = 8;
const int EPOLL_USE_CHANGELIST = 16;
/* 方法 */
public __construct( EventConfig $cfg = ?)
public dispatch(): void
public exit( float $timeout = ?): bool
public free(): void
public getFeatures(): int
public getMethod(): string
public getTimeOfDayCached(): float
public gotExit(): bool
public gotStop(): bool
public loop( int $flags = ?): bool
public priorityInit( int $n_priorities ): bool
public reInit(): bool
public stop(): bool



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".


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".


Configuration flag. Do not allocate a lock for the event base, even if we have locking set up".


Windows-only configuration flag. Enables the IOCP dispatcher at startup.


Configuration flag. Instead of checking the current time every time the event loop is ready to run timeout callbacks, check after each timeout callback.


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_CHANGELIST environment variable.

This flag has no effect if one winds up using a backend other than epoll .



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