Here are the data structures with brief descriptions:

CXtAggregateDeviceParams	Device-specific parameters for opening an aggregate audio stream
CXtAggregateStreamParams	Stream parameters specific to aggregated audio streams
CXtAttributes	Sample type attributes
CXtBuffer	Streaming audio buffer
CXtBufferSize	Device buffer size limits
CXtChannels	Audio channel specification
CXtDeviceStreamParams	Stream parameters specific to regular (non-aggregated) audio streams
CXtErrorInfo	Useful error details derived from XtError opaque error code
CXtFormat	Audio stream format
CXtLatency	Stream latency
CXtMix	Audio mix format
CXtServiceError	Platform-independent error details
CXtStreamParams	Shared parameters for regular and aggregate audio streams
CXtVersion	XT-Audio library version information