Lightweight push-only event emitter. More...

#include <jh/asynchronous/slot.h>

Public Member Functions
void	connect (listener< T > *l) noexcept
	Connect this signal to a listener.
template<typename... Args>
bool	emit (Args &&... args)
	Emit a value to the connected listener.

Detailed Description

template<typename T>
class jh::async::event_signal< T >

Lightweight push-only event emitter.

Positioning

An event_signal provides a user-facing injection mechanism. It does not store or buffer events. It only forwards emit() into its connected listener.

event_signal can have a shorter lifespan than the connected listener, but it cannot have a longer lifespan (dangling). In particular, after a slot coroutine switches the listening object between different states, the event_signal can be recycled by running out of scope.

Semantics

connect(listener*) must be called before the first emit().
emit() must be called after the slot has been spawned.
emit(...) delegates synchronously to listener.invoke().
If the hub's mutex cannot be acquired in time, the event is rejected.

Template Parameters

T	Payload type.

Note: An event_signal never performs fan-out nor routing. All routing, filtering, switching and fan-out are handled inside the slot coroutine.

Warning: Must not outlive the listener it is connected to.

Member Function Documentation

◆ connect()

template<typename T>

void jh::async::event_signal< T >::connect ( listener< T > * l )

inlinenoexcept

Connect this signal to a listener.

The signal will deliver emitted events to this listener.

Parameters

l	Pointer to the listener.

◆ emit()

template<typename T>

template<typename... Args>

bool jh::async::event_signal< T >::emit ( Args &&... args )

inline

Emit a value to the connected listener.

Invokes listener's inbox delivery logic with constructed value.