KbEventGet - aleslab/Psychtoolbox-3-aleslab-fork GitHub Wiki

[event, nremaining] = KbEventGet([deviceIndex][, maxWaitTimeSecs=0])

Return oldest pending event, if any, in return argument 'event', and the
remaining number of recorded events in the event buffer of a keyboard
queue in the return argument 'nremaining'.

By default, the event buffer of the default keyboard queue is checked,
but you can specify 'deviceIndex' to check the buffer of the queue
associated with 'deviceIndex'.

KbEventGet() will wait up to 'maxWaitTimeSecs' seconds for at least one
event to show up before it gives up. By default, it doesn't wait but just
gives up if there aren't any events queued at time of invocation.

'event' is either empty if there aren't any events available, or it is a
struct with information about the keyboard event. The returned event
struct currently contains the following fields:

'Keycode' = The KbCheck / KbName style keycode of the key or button that
triggered this event.

'Time' = The GetSecs time of when the event was received.

'Pressed' = 1 for a key press event, 0 for a key release event.

'CookedKey' = Keycode translated into a GetChar() style ASCII character code.
Or zero if key does not have a corresponding character. Or -1 if mapping
is unsupported for given event. This does not yet work correctly on OSX.

Keyboard event buffers are a different way to access the information
collected by keyboard queues. Before you can use an event buffer you
always must create its "parent keyboard queue" via KbQueueCreate() and
call KbQueueStart() to enable key event recording. See "help
KbQueueCreate" etc. on how to do this.

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See also: KbQueueCreate, KbQueueStart, KbQueueStop, KbQueueCheck,
KbQueueWait, KbQueueFlush, KbQueueRelease