EventLoop Class Reference

#include <Pt/System/EventLoop.h>

Event loop of a thread or process. More...

Inherits Connectable, and EventSink.

Inherited by MainLoop.

Public Member Functions
virtual	~EventLoop ()
	Destructor.
void	run ()
	Starts the loop.
void	exit ()
	Stops the loop.
void	processEvents ()
	Process all queued events.
Signal< const Event & > &	eventReceived ()
	Reports all events.
Signal &	exited ()
	Emited when the eventloop is exited.
AsyncYield	yieldAsync ()
	Pauses a coroutine and delegates execution back to the loop.
void	post (Selectable &s)
	Posts the loop to run a selectable.
void	setReady (Selectable &s)
	Sets the Selectable as ready without waking the loop.
void	commitEvent (const Event &ev)
	Queues an event and triggers event processing.
void	queueEvent (const Event &ev)
	Only queues an event.
void	wake ()
	Triggers event processing.

Protected Member Functions
virtual void	onCommitEvent (const Event &ev)=0
	Queues an event and triggers event processing.
virtual void	onQueueEvent (const Event &ev)=0
	Only queues an event.
virtual void	onWake ()=0
	Triggers event processing.

Detailed Description

EventLoop is the dispatch core of a thread or process. It monitors Selectable objects and Timer objects and delivers queued events. A process often runs one loop in the main thread. A second loop can run in another Thread.

The loop is an EventSink. commitEvent() queues an event and wakes the loop. queueEvent() queues without waking, so several events can be added and then released with one wake(). Events are delivered on eventReceived in the thread that called run(), in the order they were queued.

run() enters the loop and returns when exit() stops it. processEvents() delivers queued events without entering run(). exited is emitted when the loop leaves run(). Delivery always happens in the loop thread, including events queued from other threads.

Member Function Documentation

yieldAsync()

AsyncYield yieldAsync

(

)

Returns

C++20 awaitable yielding execution to the loop processing queue.

post()

void post

(

Selectable &

s

)

The event loop is woken up and the selectable's run function is called in the event loop thread. This function may be called from any thread, especially from a selectable, that is based on a parallel execution model e.g. using a worker thread.