FIX: Mfc70.lib Does Not Export AfxGetModuleThreadState (316312)
The information in this article applies to:
- Microsoft Visual C++ .NET (2002)
This article was previously published under Q316312 SYMPTOMS When you develop a Microsoft Foundation Class (MFC)
application in Microsoft Visual Studio .NET, you can use the AfxGetModuleThreadState function in debug builds. However, in release builds, the link
process fails with the message that AfxGetModuleThreadState is an unresolved external call. CAUSE In the retail version of Visual Studio .NET, Mfc70.lib does
not export the undocumented AfxGetModuleThreadState function. In the debug version of Visual Studio .NET, Mfc70d.lib
exports the AfxGetModuleThreadState function. RESOLUTION Undocumented functions such as AfxGetModuleThreadState are not guaranteed to be compatible across versions. These
functions are designed for use exclusively in internal MFC library code.
Application developers must assume the risk of using undocumented calls.
However, the AfxGetModuleThreadState function is useful to application developers who must use the
common ToolTip control. In Visual C++ 6.0, this function is used commonly in
the following manner:
CToolTipCtrl* pToolTipCtrl = AfxGetModuleThreadState()->m_pToolTip;
For Visual C++ .NET, this approach fails in a release build.
Alternatively, you can use the following method:
CToolTipCtrl* pToolTipCtrl = AfxGetModuleState()->m_thread.GetDataNA()->m_pToolTip;
You can use this method to retrieve other thread-specific data
elements, also. For example, if a socket window is associated with a thread,
you can retrieve the socket window handle this manner through the m_hSocketWindow variable. STATUSMicrosoft 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 Microsoft Visual C++ .NET (2003).
MORE INFORMATION Because MFC uses a common ToolTip control, some
applications access the MFC ToolTip control through the thread-specific storage
in MFC. The ToolTip control, which is stored in the thread data structure, is
shared so that each application does not have to have a separate ToolTip
control. As a result of this access method, you can call GetToolTips in the CToolBarCtrl class and receive a null return value. REFERENCESFor
additional information, click the article number below to view the article in
the Microsoft Knowledge Base: 151894 PRB: CToolBarCtrl::GetToolTips() May Return NULL for a ToolBar
154649 FIX: CSocket Operation Hangs if a Timer is Active
193101 FIX: Unhandled Exception Using MFC Sockets in Visual C++ 6.0
| Modification Type: | Major | Last Reviewed: | 4/11/2003 |
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| Keywords: | kbfix kbbug kbCmnCtrls kbpending KB316312 |
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