The Event class

Intro

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

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 writing.

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.

Event