I'm writing an ALSA demonstration program which, by almost any standards, is a "filter": read sequencer events, decide what to do with them, and either emit, dump to stdout or ignore.
I find reference in the API documentation to snd_seq_client_info_event_filter_add() and related functions, but nowhere can I find anything about what they actually do and how they should be used. As a result, I can't determine whether they are something I really should be using.
I've previously found ALSA input from MIDI keyboard which helped with the device connection side. Can anybody (please) throw any light on the filter API?