DOCUMENT:Q100030  05-NOV-1999  [win16sdk]
TITLE   :PRB: midiInputHandler GP faults in MIDIMON Sample Application
PRODUCT :Microsoft Windows Software Development Kit
PROD/VER:WINDOWS:3.0,3.1
OPER/SYS:
KEYWORDS:kb16bitonly

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The information in this article applies to:

 - Microsoft Windows Software Development Kit (SDK) versions 3.0, 3.1 
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SYMPTOMS
========

In the MIDIMON sample application provided with Visual C++ and the Microsoft
Windows Software Development Kit (SDK) version 3.1, the midiInputHandler()
callback function causes a general protection (GP) fault.

CAUSE
=====

The GP fault occurs when the MIDI event handler tries to store event data in a
static variable, but the data segment (DS) is not set correctly because the
exported functions in the callback dynamic-link library (DLL) are not exported
correctly.

RESOLUTION
==========

Because the /GD compiler option is specified in the makefile for MIDIMON's
callback DLL, the DLL's exported functions must be declared with the __export
keyword. The exported functions missing the __export keyword are _WEP(),
midiInputHandler(), and PutEvent(). The __export keyword should be added as
required in CALLBACK.H and CALLBACK.DEF.

MORE INFORMATION
================

The problem described above exists only in the version of MIDIMON distributed
with Visual C++ (Microsoft C version 8.0); the original version distributed with
C 7.0 builds correctly as shipped.

Additional query words: 3.10 gp-fault gpf midi

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK300 kbWinSDK310
Version           : WINDOWS:3.0,3.1

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