Microsoft KB Archive/105760

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Using VxDs and Software Interrupts Under Win32s

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Q105760

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The information in this article applies to:


 * Microsoft Win32s versions 1.3, 1.30a, 1.3c

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SUMMARY
Calling VxDs directly from a Win32-based application is not supported under Win32s. Win32s does not support the VxD interfaces, so the call is handled by the underlying Windows system. The Win32-based application runs with 32-bit stack and code sections, but Windows expects only 16-bit segments. Therefore, the calls to the VxD cannot be handled by Windows as expected.

To call software interrupts (such as Interrupt 2F) from a Win32-based application running under Windows 3.1 via Win32s, place the call in a 16- bit dynamic-link library (DLL) and use the Universal Thunks to access this DLL. To convert the addresses between segmented and linear address, use UTSelectorOffsetToLinear and UTLinearToSelectorOffset.

Additional query words:

Keywords : kbOSWin32s kbThunks

Issue type :

Technology : kbWin32sSearch kbWin32s130 kbWin32s130a kbWin32s130c