DOCUMENT:Q98379  12-NOV-1999  [miscsdk]
TITLE   :BUG: xlCoerce() Can Cause GP Fault in EXCEL.EXE
PRODUCT :Miscellaneous Software Development Kits
PROD/VER::
OPER/SYS:
KEYWORDS:

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The information in this article applies to:

 - Microsoft Excel Software Development Kit 
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SYMPTOMS
========

Calling xlCoerce() from a dynamic-link library (DLL) function causes a general
protection (GP) fault in the following circumstances:

 - The source XLOPER is xltypeRef or xltypeSRef

 - The destination XLOPER is xltypeMulti

 - The source reference contains one or more uncalculated cells

Consider the following code fragment:

      xlDest.xltype = xltypeInt;
      xlDest.val.w  = xltypeMulti;

      Excel4(
         xlCoerce,
         &xlResult,
         2,
         (LPXLOPER) &xlSource,
         (LPXLOPER) &xlDest
      );

This code causes a GP fault if xlSource is type xltypeSRef or xltypeRef, and
xlSource references uncalculated cells.

CAUSE
=====

This is caused by a problem in Excel 4.0.

RESOLUTION
==========

The workaround for this problem is to use xlCoerce() to individually look up
cells in xltypeSRef or xltypeRef. The Software/Data Library contains a modified
version of the Framework library that demonstrates this method. For more
information, query on the following keywords:

   p_xlsdk and softlib and framewrk

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft Excel version 4.0. We
are researching this problem and will post new information here as it becomes
available.

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

This problem can be reproduced using the FuncSum() function provided by the
Excel SDK GENERIC sample:

1. Load GENERIC.XLL.

2. Enter these formulae on a worksheet:

   a. A1: =RAND()

   b. A2: =A1

   c. A3: =FuncSum(A1:A2)

   d. A1: =2

Changing cell A1 from 1 to 2 causes FuncSum() to recalculate. Cell A2 is still
uncalculated at that point, and Microsoft Excel will crash. This behavior
results from the problem with the xlCoerce() function.


Additional query words: crash gp-fault

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Keywords          :  
Technology        : kbExcelSearch kbAudDeveloper kbSDKExcelSearch kbSDKSearch
Version           : :

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