Module audio::jack_lib

audio & MIDI: libjack, loaded at run time.

std-private: the JACK functions std/audio's JACK backends (audio_jack_posix.sc for audio, midi_jack_posix.sc for MIDI) call, looked up with dlsym() from libjack.so.0 (libjack.0.dylib on macOS) so builds don't link libjack and run without it. Function signatures follow <jack/jack.h> and <jack/midiport.h>; jack_nframes_t is uint32, size_t is pointer width.