For a description of handling the error return values from DriverProc for system messages, see the description of installable device drivers in the Microsoft Windows Software Development Kit. The following list summarizes the joystick error codes defined in MMSYSTEM.H:
MMSYSERR_NOERROR
No error.
MMSYSERR_NODRIVER
No joystick device driver is present.
JOYERR_PARMS
Invalid parameters were passed with the message.
JOYERR_NOCANDO
Driver cannot perform the requested task because some service is unavailable.
JOYERR_UNPLUGGED
Specified joystick is unplugged.