Microsoft KB Archive/175378

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DOC: Interrupt 2Fh Function 1684h Name-based Usage

Q175378

The information in this article applies to:

Microsoft Win32 Device Driver Kit (DDK) Windows 95, on platform(s):
- the operating system: Microsoft Windows 95

SUMMARY

The Windows 95 Device Driver Kit documentation describes how a 16-bit ring 3 application can retrieve the entry point for a VxD's service functions, by specifying the VxD's unique device ID. The documentation omitted an alternate way to specify a VxD by indicating its VxD name. The sample below demonstrates how to do this:

   xor   bx, bx      ; bx = 0 indicates name-based
   les   di, lpName  ; Name of device being queried
   int   2Fh

   mov   word ptr [DevAddr], di
   mov   word ptr [DevAddr+2], es ; ES:DI contains entry point addr
   or    di, word ptr [DevAddr+2] ; or contains 0:0 on error
   jz    Error

In the documentation of the parameters, please add

DeviceID
Identifies a virtual device. If this value is zero, then the ES:DI registers point to an 8-character space-padded case-sensitive device name.

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Technology : kbAudDeveloper kbWinDDKSearch kbWin32sSearch kbWin32DDKSearch