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Q121416: PRB: GetPrivateProfileString() Generates "Data Type Mismatch"

Article: Q121416
Product(s): Microsoft FoxPro
Version(s): 2.5x 2.60 2.60a 3.00
Operating System(s): 
Keyword(s): 
Last Modified: 20-AUG-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
- Microsoft FoxPro for Windows, versions 2.x, 2.6, 2.6a 
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SYMPTOMS
========

When you call the GetPrivateProfileString) Windows API function from within
FoxPro for Windows and the UDFPARMS setting is REFERENCE, you will receive the
error message "Data type mismatch."

CAUSE
=====

This error occurs because GetPrivateProfileString() is expecting certain
parameters to be passed by VALUE. With the UDFPARMS set to REFERENCE, you are
sending all parameters by REFERENCE. The GetPrivateProfileString() function
returns an error because it is expecting these parameters by VALUE. FoxPro
interprets the error as a data type mismatch.

RESOLUTION
==========

To prevent this behavior, set UDFPARMS to VALUE.

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

Steps to Reproduce Behavior
---------------------------

Type the following commands in the Command window:

     SET LIBRARY TO SYS(2004)+"FOXTOOLS.FLL"
     MRETURN=REPLICATE(CHR(0), 144)
     MREGISTER=REGFN("GETPRIVATEPROFILESTRING","CCC@CI","I")
     MCALL=CALLFN(MREGISTER,"WINDOWS","LOAD","",@MRETURN,256)

The last command will return the error message "Data type mismatch."

NOTE: A "FOXPROW caused a General Protection Fault in module <unknown>"
error message occurs if UDFPARMS is set to VALUE.

Additional query words: VFoxWin FoxWin 2.50 2.50a 2.50b errmsg

======================================================================
Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbFoxproSearch kbFoxPro260 kbFoxPro260a kbVFP300
Version           : 2.5x 2.60 2.60a 3.00

=============================================================================

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