Microsoft KB Archive/217201

= FIX: CControlBar Crashes When TOOLTIPTEXT.lpszText Is the ID for a String Resource =

Article ID: 217201

Article Last Modified on 11/21/2006

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APPLIES TO

 Microsoft Foundation Class Library 4.2, when used with:  Microsoft Visual C++ 6.0 Enterprise Edition

 Microsoft Visual C++ 6.0 Professional Edition

 Microsoft Visual C++ 6.0 Standard Edition 

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This article was previously published under Q217201

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SYMPTOMS
An access violation occurs with the CControlBar::WindowProc file when executing the statement: if ((pNMHDR->code == TTN_NEEDTEXTA && (!pTTTA->lpszText || !*pTTTA->lpszText)) || (pNMHDR->code == TTN_NEEDTEXTW && (!pTTTW->lpszText || !*pTTTW->lpszText))) This statement is at line 457 in the Barcore.cpp file.

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CAUSE
The assertion occurs in the preceding code if the lpszText member of the TOOLTIP structure is an identifier of a string resource. In this case, the code is trying to dereference a pointer; however, *pTTTA->lpszText is "pointing" to a value instead of a valid memory location.

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RESOLUTION
Copy the address of the buffer that contains the text to the lpszText TOOLTIP member. If the text to appear as tool tip text is stored as a string resource, use the LoadString function to load the string from the string table into a buffer and assign that buffer to the lpszText TOOLTIP member.

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STATUS
Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information about Visual Studio service packs, please see the following articles in the Microsoft Knowledge Base:

194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

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MORE INFORMATION
This bug was introduced in Visual C++ version 6.0 with the reimplementation of the CControlBar::WindowProc function.

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