Using VxDs and Software Interrupts Under Win32s

Last reviewed: April 7, 1997
Article ID: Q105760

1.30 1.30a 1.30c WINDOWS kbprg kbhowto

The information in this article applies to:

Microsoft Win32s versions 1.30, 1.30a, and 1.30c

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().

KBCategory: kbprg kbhowto
KBSubcategory: W32s
Additional reference words: 1.30 1.30a 1.30c
Keywords : W32s W32sThunk kbhowto kbprg
Version : 1.30 1.30a 1.30c
Platform : WINDOWS

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Last reviewed: April 7, 1997
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