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Copyright (C) 4Front Technologies, 2002-2004. Released under GPLv2/CDDL.
This program does nothing but plays a note on MIDI channel 1 after sending a program change message.
This program demonstrates how simple it's to write programs that play MIDI. All you need to do is assembling the MIDI message and writing it to the device. The MIDI format is defined in "MIDI 1.0 Detailed Specification" which is available from MIDI Manufacturs Association (MMA) (see http://www.midi.org ).
This program does timing by calling the sleep(3) system call. In some systems like Linux there may be better sleep routines like usleep(3) that provide better timing resolution.
However application based timing may not be as precise as required in musical applications. For this reason the MIDI interface of OSS will provide a driver based timing approach in the near future.
Please look at the "OSS MIDI Programming" section of the OSS Developer's manual for more info about MIDI programming.
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
#include <soundcard.h>
#define DEVICE "/dev/midi"
int
main ()
{
int fd;
unsigned char note_on[] = { 0xc0, 0, /* Program change */
0x90, 60, 60
}; /* Note on */
unsigned char note_off[] = { 0x80, 60, 60 }; /* Note off */
if ((fd = open (DEVICE, O_WRONLY, 0)) == -1)
{
perror ("open " DEVICE);
exit (-1);
}
if (write (fd, note_on, sizeof (note_on)) == -1)
{
perror ("write " DEVICE);
exit (-1);
}
sleep (1); /* Delay one second */
if (write (fd, note_off, sizeof (note_off)) == -1)
{
perror ("write " DEVICE);
exit (-1);
}
close (fd);
exit (0);
}