Public Member Functions | List of all members
WaitableEvent Class Reference

Allows threads to wait for events triggered by other threads. More...

Public Member Functions

 WaitableEvent (bool manualReset=false) noexcept
 Creates a WaitableEvent object. More...
 
 ~WaitableEvent () noexcept
 Destructor. More...
 
bool wait (int timeOutMilliseconds=-1) const noexcept
 Suspends the calling thread until the event has been signalled. More...
 
void signal () const noexcept
 Wakes up any threads that are currently waiting on this object. More...
 
void reset () const noexcept
 Resets the event to an unsignalled state. More...
 

Detailed Description

Allows threads to wait for events triggered by other threads.

A thread can call wait() on a WaitableObject, and this will suspend the calling thread until another thread wakes it up by calling the signal() method.

Constructor & Destructor Documentation

◆ WaitableEvent()

WaitableEvent::WaitableEvent ( bool  manualReset = false)
explicitnoexcept

Creates a WaitableEvent object.

The object is initially in an unsignalled state.

Parameters
manualResetIf this is false, the event will be reset automatically when the wait() method is called. If manualReset is true, then once the event is signalled, the only way to reset it will be by calling the reset() method.

◆ ~WaitableEvent()

WaitableEvent::~WaitableEvent ( )
noexcept

Destructor.

If other threads are waiting on this object when it gets deleted, this can cause nasty errors, so be careful!

Member Function Documentation

◆ wait()

bool WaitableEvent::wait ( int  timeOutMilliseconds = -1) const
noexcept

Suspends the calling thread until the event has been signalled.

This will wait until the object's signal() method is called by another thread, or until the timeout expires.

After the event has been signalled, this method will return true and if manualReset was set to false in the WaitableEvent's constructor, then the event will be reset.

Parameters
timeOutMillisecondsthe maximum time to wait, in milliseconds. A negative value will cause it to wait forever.
Returns
true if the object has been signalled, false if the timeout expires first.
See also
signal, reset

◆ signal()

void WaitableEvent::signal ( ) const
noexcept

Wakes up any threads that are currently waiting on this object.

If signal() is called when nothing is waiting, the next thread to call wait() will return immediately and reset the signal.

If the WaitableEvent is manual reset, all current and future threads that wait upon this object will be woken, until reset() is explicitly called.

If the WaitableEvent is automatic reset, and one or more threads is waiting upon the object, then one of them will be woken up. If no threads are currently waiting, then the next thread to call wait() will be woken up. As soon as a thread is woken, the signal is automatically reset.

See also
wait, reset

◆ reset()

void WaitableEvent::reset ( ) const
noexcept

Resets the event to an unsignalled state.

If it's not already signalled, this does nothing.


The documentation for this class was generated from the following file: