The messages the virtual pen driver can receive are listed in the following table.
| Message | Description |
|---|---|
| VPEND_DISABLE | Calls cVpenD_API_Disable to disable the tablet. |
| VPEND_ENABLE | Calls cVpenD_API_Enable to enable the tablet. |
| VPEND_FREE | Frees all resources used to monitor the pen device and decrements the number of installed drivers. |
| VPEND_GETCALIBRATION | Determines hardware calibration information and puts it into a DRV_CALBSTRUCT structure provided by the caller. |
| VPEND_GETPENINFO | For a pen driver that supports more than one virtual machine (VM), copies the pen information for the current VM to a DRV_PENINFO structure provided by the caller. The sample pen driver does not use a VPEND_GETPENINFO message. |
| VPEND_LOAD | Initializes variables so the tablet can later be enabled. |
| VPEND_OEM | An OEM-specific message which is passed through to the OEM-provided part of the virtual pen driver. |
| VPEND_PENPLAYBACK | Starts playing back an array of stored pen packets, substituting the stored pen packets for pen packets assembled from tablet interrupt information. |
| VPEND_PENPLAYSTART | Puts the virtual pen driver in playback mode by setting up all data structures necessary to act on the next VPEND_PENPLAYBACK message received. |
| VPEND_PENPLAYSTOP | Takes the virtual pen driver out of playback mode. |
| VPEND_SETCALIBRATION | Sets calibration values in the hardware information structure. |
| VPEND_SETSAMPLINGDIST | Sets the sampling distance. The sample virtual pen driver sets the new sampling distance value in the DRV_PENINFO structure but does not call an OEM-supplied code to set the sampling rate. |
| VPEND_SETSAMPLINGRATE | Calls OEM-supplied, device-specific code to set the tablet sampling rate. |