Using VxDs and Software Interrupts Under Win32s

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          : kbWin32s kbThunk 
Version           : 1.30 1.30a 1.30c
Platform          : WINDOWS

Last Reviewed: April 9, 1997