Call this macro to protect an exported function in a DLL.
When this macro is invoked, pModuleState is the effective module state for the remainder of the immediate containing scope. Upon leaving the scope, the previous effective module state will be automatically restored.
The AFX_MODULE_STATE structure contains global data for the module, that is, the portion of the module state that is pushed or popped.
By default, MFC uses the resource handle of the main application to load the resource template. If you have an exported function in a DLL, such as one that launches a dialog box in the DLL, this template is actually stored in the DLL module. You need to switch the module state for the correct handle to be used. You can do this by adding the following code to the beginning of the function:
This swaps the current module state with the state returned from AfxGetStaticModuleState until the end of the current scope.
When MFC creates an activation context for an assembly, it uses AfxWinInit to create the context and AFX_MANAGE_STATE to activate and deactivate it. Note also that as of Visual C++ 2005, the behavior of AFX_MANAGE_STATE has changed in that it is enabled for static MFC libraries, as well as MFC DLLs, in order to allow MFC code to execute in the proper activation context selected by the User DLL. For more information, see Support for Activation Contexts in the MFC Module State.