Hook notifying you when new midi data becomes available. allegro game programming library.
#include <allegro.h>
extern void (*midi_recorder)(unsigned char data);
If set, this function is called by the MIDI input driver whenever a new byte of MIDI data becomes available. It runs in an interrupt context, so it must execute very quickly and all the code/data must be locked. This currently works only under DOS and Windows.
install_sound_input(3alleg4), midi_out(3alleg4)