VMPages: A VxD that Exports a VMM Service to an Application

VMPages is a virtual device (VxD) that demonstrates how to export a VxD service (in this case _GetVMPgCount), to an application. VMPGS.EXE is an MS-DOS(R) application that calls the API that VMPAGES exports. Although VMPages and VMPGS are very simple and very incomplete samples, they illustrate the essential requirements for exporting an API from a VxD to an application.

To use VMPages, place VMPAGES.386 in the Windows SYSTEM directory and add the following line to the [386Enh] section of your SYSTEM.INI file:

DEVICE=VMPAGES.386

Run Windows under WDEB386 (or any other debugger that traps Interrupt 01), and then run VMPGS.EXE inside Windows. Using the debugger, examine the buffer returned after Interrupt 01.

This sample code requires special VxD tools and include files; see the "VxD Tools" and "VxD Include Files" abstracts to copy these files to your development system. For more information on using the Microsoft Windows version 3.1 Device Driver Kit (DDK) files included on this CD, read the technical article "The VxD-Lite Mini-DDK." For more information on virtual device programming, see the DDK "Virtual Device Adaptation Guide."

VMPages was built and tested under Microsoft Windows version 3.1.

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