Event
PHP Manual

The Event class

Introduction

Event class represents and event firing on a file descriptor being ready to read from or write to; a file descriptor becoming ready to read from or write to(edge-triggered I/O only); a timeout expiring; a signal occurring; a user-triggered event.

Every event is associated with EventBase . However, event will never fire until it is added (via Event::add ). An added event remains in pending state until the registered event occurs, thus turning it to active state. To handle events user may register a callback which is called when event becomes active. If event is configured persistent , it remains pending. If it is not persistent, it stops being pending when it's callback runs. Event::del method deletes event, thus making it non-pending. By means of Event::add method it could be added again.

Class synopsis

Event
final class Event {
/* Constants */
const int Event::ET = 32;
const int Event::PERSIST = 16;
const int Event::READ = 2;
const int Event::WRITE = 4;
const int Event::SIGNAL = 8;
const int Event::TIMEOUT = 1;
/* Properties */
public readonly bool $pending;
/* Methods */
public bool add( float $timeout = ?)
public __construct(
     EventBase $base ,
     mixed $fd ,
     int $what ,
     callable $cb ,
     mixed $arg = NULL
)
public bool del()
public void free()
public static array getSupportedMethods()
public bool pending( int $flags )
public bool set(
     EventBase $base ,
     mixed $fd ,
     int $what = ?,
     callable $cb = ?,
     mixed $arg = ?
)
public bool setPriority( int $priority )
public bool setTimer( EventBase $base , callable $cb , mixed $arg = ?)
public static Event signal(
     EventBase $base ,
     int $signum ,
     callable $cb ,
     mixed $arg = ?
)
public static Event timer( EventBase $base , callable $cb , mixed $arg = ?)
}

Properties

pending

Whether event is pending. See About event persistence .

Predefined Constants

Event::ET

Indicates that the event should be edge-triggered, if the underlying event base backend supports edge-triggered events. This affects the semantics of Event::READ and Event::WRITE .

Event::PERSIST

Indicates that the event is persistent. See About event persistence .

Event::READ

This flag indicates an event that becomes active when the provided file descriptor(usually a stream resource, or socket) is ready for reading.

Event::WRITE

This flag indicates an event that becomes active when the provided file descriptor(usually a stream resource, or socket) is ready for reading.

Event::SIGNAL

Used to implement signal detection. See "Constructing signal events" below.

Event::TIMEOUT

This flag indicates an event that becomes active after a timeout elapses.

The Event::TIMEOUT flag is ignored when constructing an event: one can either set a timeout when event is added , or not. It is set in the $what argument to the callback function when a timeout has occurred.

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