BlitzMax/Modules/Events/Event queue

The event queue is a simple first-in, first-out queue that is used to collect TEvent objects emitted by your application.

The PollEvent and WaitEvent commands can be used to receive the next event from the event queue, while the PeekEvent command can be used to check if the event queue is empty.

Events are added to the event queue using PostEvent.

=Globals=

CurrentEvent
Global CurrentEvent:TEvent=NullEvent

Description: Current Event

Information: The CurrentEvent global variable contains the event most recently returned by PollEvent or WaitEvent.

=Functions=

PeekEvent
Function PeekEvent:TEvent

Description: Examine the next event in the event queue

Information: PeekEvent examines the next event in the event queue, without removing it from the event queue or modifying the CurrentEvent global variable.

If there are no events in the event queue, PeekEvent returns Null.

PollEvent
Function PollEvent

Description: Get the next event from the event queue

Returns: The id of the next event in the event queue, or 0 if the event queue is empty

Information: PollEvent removes an event from the event queue and updates the CurrentEvent global variable.

If there are no events in the event queue, PollEvent returns 0.

WaitEvent
Function WaitEvent

Description: Get the next event from the event queue, waiting if necessary

Returns: The id of the next event in the event queue

Information: WaitEvent removes an event from the event queue and updates the CurrentEvent global variable.

If there are no events in the event queue, WaitEvent halts program execution until an event is available.

PostEvent
Function PostEvent( event:TEvent,update=False )

Description: Post an event to the event queue

Information: PostEvent adds an event to the end of the event queue.

The update flag can be used to update an existing event. If update is True and an event with the same id and source is found in the event queue, the existing event will be updated instead of event being added to the event queue. This can be useful to prevent high frequency events such as timer events from flooding the event queue.

EventID
Function EventID

Description: Get current event id

Returns: The id field of the CurrentEvent global variable

EventData
Function EventData

Description: Get current event data

Returns: The data field of the CurrentEvent global variable

EventMods
Function EventMods

Description: Get current event modifiers

Returns: The mods field of the CurrentEvent global variable

EventX
Function EventX

Description: Get current event x value

Returns: The x field of the CurrentEvent global variable

EventY
Function EventY

Description: Get current event y value

Returns: The y field of the CurrentEvent global variable

EventExtra
Function EventExtra:Object

Description: Get current event extra value

Returns: The extra field of the CurrentEvent global variable

EventText
Function EventText$

Description: Get current event extra value converted to a string

Returns: The extra field of the CurrentEvent global variable converted to a string

EventSource
Function EventSource:Object

Description: Get current event source object

Returns: The source field of the CurrentEvent global variable

EventSourceHandle
Function EventSourceHandle

Description: Get current event source object handle

Returns: The source field of the CurrentEvent global variable converted to an integer handle