MMSYSTEM sends the JDD_GETDEVCAPS message to request information about the coordinate range and button configuration of a joystick driver. In response to this message, a joystick driver fills in the JOYCAPS structure, a pointer to it is passed to the lParam1 parameter. The JOYCAPS structure members describe the coordinate range, button configuration, and manufacturer of the device.
The minimum and maximum position values should reflect a set of logical coordinates that is independent of minute differences between copies of a hardware device. For example, users of joystick services should always see a full range of logical coordinates returned from a calibrated joystick. Calibration values should not affect the minimum and maximum values returned by a joystick driver. The IBMJOY example device driver Windows returns coordinate values in the range 0 through 65535.
If a hardware device does not support a given axis, return zero values for the minimum and maximum coordinate values for that axis. For example, a driver for a two-dimensional device would set the wZmin and wZmax members to zero.