opendarwin man page for detect_midi_driver

detect_midi_driver(3alleg4)					  Allegro manual				       detect_midi_driver(3alleg4)

NAME
       detect_midi_driver - Detects whether the specified MIDI sound device is available. Allegro game programming library.

SYNOPSIS
       #include <allegro.h>

       int detect_midi_driver(int driver_id);

DESCRIPTION
       Detects whether the specified MIDI sound device is available. This function must be called _before_ install_sound().

RETURN VALUE
       Returns the maximum number of voices that the driver can provide, or zero if the hardware is not present.

       There  are two special-case return values that you should watch out for: if this function returns -1 it is a note-stealing driver (eg. DIG-
       MID) that shares voices with the current digital sound driver, and if it returns 0xFFFF it is an external  device  like	an  MPU-401  where
       there is no way to determine how many voices are available.

SEE ALSO
       install_sound(3alleg4), reserve_voices(3alleg4)

Allegro 							   version 4.4.2				       detect_midi_driver(3alleg4)