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Q98379: BUG: xlCoerce() Can Cause GP Fault in EXCEL.EXE

Article: Q98379
Product(s): Miscellaneous Software Development Kits
Version(s): 
Operating System(s): 
Keyword(s): 
Last Modified: 12-NOV-1999

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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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