Playing MIDI using raw WIN32 API

How-To-Play-MIDI-WIN32.c

// Step 1. Open default MIDI-device or die
int rc = midiOutOpen(&midi_device, 0, 0, 0, CALLBACK_NULL);
if (rc != MMSYSERR_NOERROR) {
  return FALSE;
}

// Step 2. Set instrument for a channel (0..15)
DWORD command = (0x000000C0 | CHANNEL) | (INSTRUMENT << 8);
midiOutShortMsg(midi_device, command);

// Step 3. "Touch" a key, sleep some, and "Release" then.
DWORD command = (0x00000090 | CHANNEL) | (KEY << 8) | (VOLUME << 16);
midiOutShortMsg(midi_device, command);
Sleep(100);
command &= 0x0000FFFF;
midiOutShortMsg(midi_device, command);

// Step 4. Reset and Close the MIDI device as no longer needed
midiOutReset(midi_device);
midiOutClose(midi_device);