DOC: AfxGetStaticModuleState() Causes Errors in an Extension DLL (161589)

SUMMARY

The Visual C++ version 4.1 MFC documentation indicates that MFC Extension DLLs need to use the macro expression "AFX_MANAGE_STATE(AfxGetStaticModuleState());" at the top of every exported DLL function. This is incorrect; MFC Extension DLLs do not need to use this expression.

This error was fixed in the documentation for Visual C++ version 4.2 and later versions of Visual C++.

MORE INFORMATION

Under the subheading "Extension DLLs" of the article "Visual C++ Books -> MFC 4.2 -> Programming with MFC:Encyclopedia - > Dynamic-Link Libraries (DLLs) -> Dynamic-Link Libraries (DLLs)," the following text appears:

"If you have a resource in your DLL, such as a dialog, you need to use the macro AFX_MANAGE_STATE to switch the MFC module state correctly, so that Windows looks in the DLL and not in the EXE for the resource. This can be done by adding the following line of code to the beginning of functions exported from the DLL:

   AFX_MANAGE_STATE(AfxGetStaticModuleState( ))"

This is incorrect. Extension DLLs do not need to add this macro at the top of every exported function . The AFX_MANAGE_STATE macro can be used inside of callbacks or custom window procedures to properly adjust the current module state, but it should be used with AfxGetAppModuleState() or a specific module state instance instead of AfxGetStaticModuleState().

Any attempt to use AfxGetStaticModuleState( ) in an Extension DLL will result in possible run-time problems and the following linker errors:

   "mfcs40d.lib(dllmodul.obj) : error LNK2005: __pRawDllMain already
   defined in testdll1.obj
   mfcs40d.lib(dllmodul.obj) : error LNK2005: _DllMain@12 already defined
   in testdll1.obj
   mfcs40d.lib(dllmodul.obj) : warning LNK4006: __pRawDllMain already
   defined in testdll1.obj; second definition ignored
   mfcs40d.lib(dllmodul.obj) : warning LNK4006: _DllMain@12 already defined
   in testdll1.obj; second definition ignored"

The incorrect paragraph was removed from the documentation for Visual C++ in version 4.2.