AuSync.3x man page
AuSync - flush the output buffer and wait for all events and errors to be processed by the server
void AuSync(server, discard)
Specifies the connection to the audio server.
Specifies if events in the input queue are discarded.
AySync flushes the output buffer, then waits until all pending requests have been received and processed by the server. If discard is AuTrue, all events on the input queue are discarded.
audiolib - Network Audio System C Language Interface