DOCUMENT:Q158552  04-AUG-2001  [visualc]
TITLE   :PRB: CPropertySheet::DoModal() or Create() Causes an Exception
PRODUCT :Microsoft C Compiler
PROD/VER:winnt:4.0,4.1,4.2,5.0,6.0
OPER/SYS:
KEYWORDS:kbcode kbMFC KbUIDesign kbVC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 kbGrpDSMFCATL

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), used with:
    - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
    - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
    - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
    - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
    - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
    - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

Calling CPropertySheet::DoModal() or CPropertySheet::Create() in Windows 95 may
cause an exception. The Output window displays a message that says the
following:

   First-chance exception in <program.exe> (Comctl32.dll): 0xC0000005:
   Access Violation.

Newer versions (version 4.70) of the Comctl32.dll do not have this problem.

CAUSE
=====

The CommCtl32.dll tries to modify the resources for the pages. Since the
resources are normally in read-only sections this throws an Exception that can
be caught in the application. However, if the application does not catch this
exception then the OS will handle this exception correctly.

RESOLUTION
==========

The first-chance exception can be ignored because it is safely handled by the
operating system.

One way to prevent the exception from being thrown is to make the resources
read/write. You can do this by adding a linker setting of "/SECTION:.rsrc,rw."

A second way to prevent the exception being thrown is to change the font of the
pages so they are not "MS Sans Serif". MFC checks the dialog template font for
the page. If it is not "MS Sans Serif" then it makes a copy of the resource in
read/write memory, modifies the font and passes this to the C mCtl32.dll. So
when the dll writes to the template for the page it is writing to read/write
memory and hence exception is not thrown.

Another way to prevent the exception from affecting your application is not to
have the call for creating the property sheet in a try/catch(...) block. Instead
catch particular exceptions in the catch block.

If the property sheet is part of an OLE Automation Server that can be invoked
through a method of the server then you have to make the resources read/write,
using either of the first two methods described above, since OLE catches the
exception.

NOTE: Making the resources Read/Write can cause the resources to be written to a
page file.

STATUS
======

This behavior is by design.

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

Sample Code
-----------

      /* Compile options needed: default
      */ 

      /***** this code will cause unpredictable results *****/ 
      try
      {
          sheet.DoModal();
      }
      catch(...)
      {
      }

      /***** this code is OK *****/ 
      try
      {
          if (0 == sheet.DoModal())
              throw "DoModal() failed!";
      }
      catch(char * str)
      {
          TRACE ("Exception thrown: %s\n", str);
      }

REFERENCES
==========

For more information, please see the following article in the Microsoft
Knowledge Base:

   Q126630 Resource Sections are Read-only

Additional query words:

======================================================================
Keywords          : kbcode kbMFC KbUIDesign kbVC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:4.0,4.1,4.2,5.0,6.0
Issue type        : kbprb

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.