Type Alias

HostCallback_GetTransportState

When called by the system, provides audio transport state and timeline information to an audio unit from a host application.

Declaration

typedef OSStatus (*HostCallback_GetTransportState)(void *inHostUserData, Boolean *outIsPlaying, Boolean *outTransportStateChanged, Float64 *outCurrentSampleInTimeLine, Boolean *outIsCycling, Float64 *outCycleStartBeat, Float64 *outCycleEndBeat);

Parameters

inHostUserData

Custom data that you provided when registering your callback with the audio unit.

outIsPlaying

On output, TRUE if audio is playing, or FALSE otherwise.

outTransportStateChanged

On output, TRUE if the transport state changed since the last time the callback was invoked, or FALSE otherwise.

outCurrentSampleInTimeLine

On output, the sample number, indexed from zero from the beginning of the timeline.

outIsCycling

On output, TRUE if cycling, or FALSE otherwise.

outCycleStartBeat

outCycleEndBeat

Discussion

If you named your callback function MyHostCallback_GetTransportState, you would declare it like this:

See Also

Callbacks

HostCallback_GetBeatAndTempo

When called by the system, provides beat and tempo information to an audio unit from a host application.

HostCallback_GetMusicalTimeLocation

When called by the system, provides musical timing information to an audio unit from a host application.

AUMIDIOutputCallback

When called by a host application, gets MIDI data from an audio unit.