HELP: how to load satellite DLL for a DLL
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Thread: HELP: how to load satellite DLL for a DLL

  1. #1
    Join Date
    Mar 2009
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    HELP: how to load satellite DLL for a DLL

    I have a Visual C++ workspace that has 2 projects (1 exe & 1 DLL).

    I used Serge Wautier's tutorial ( http://www.codeproject.com/Articles/...Selection-Menu ) to create (multi-language) resource DLLs (satellite DLLs) branching off the exe.

    Now I have a collection of strings in the DLL that are shared in other projects. I created a satellite DLL for that DLL but can't figure out how to load it on-demand just like the exe's satellite DLL.

    He used:
    HINSTANCE hDll = LoadLibrary(szFilename);
    AfxSetResourceHandle(hDll);

    void CLanguageSupport::UnloadResourceDll()
    {
    if (m_hDll!=NULL)
    {
    SetResourceHandle(AfxGetApp()->m_hInstance); // Restores the EXE as the resource container.
    FreeLibrary(m_hDll);
    m_hDll= NULL;
    }
    }

    etc etc for the unloading/loading satellite DLLs for the exe.
    but how to do the same for the DLL?

  2. #2
    Join Date
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    Re: HELP: how to load satellite DLL for a DLL

    And what is your problem to do the same for Dll?
    Best regards,
    Igor

  3. #3
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    Re: HELP: how to load satellite DLL for a DLL

    Quote Originally Posted by Igor Vartanov View Post
    And what is your problem to do the same for Dll?
    The exe project is statically linked to my other DLL project via the linker lib. So it's loaded automatically. Am not sure how to create a satellite DLL for that DLL, nor how to unload/reload it, etc.

  4. #4
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    Re: HELP: how to load satellite DLL for a DLL

    Just forget about the way how your EXE is linked to DLL.

    If the linked DLL is yours, the code for loading/unloading external resource DLL must be in the DLL that external resources are intended for, and the code will be pretty much the same to what you quoted.

    If the DLL is not yours, you are not able to control the way how it handles resources. With all the consequences.

    In case the external resources are intended for both EXE and DLL, the resource handle may be controlled by EXE code which will propagate the changed module handle to the linked DLL as well. Of course, the linked DLL must be designed to accept the changes.
    Best regards,
    Igor

  5. #5
    Join Date
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    Re: HELP: how to load satellite DLL for a DLL

    I think I got it working:

    From VC2005 there's a function called AddResourceInstance() to chain DLLs. However am still using VC6 so this function doesn't exist.

    So I just copied some code from a DLL project. The DLL main file contains these lines:

    Code:
    static AFX_EXTENSION_MODULE NEAR extensionDLL = { NULL, NULL };
    DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)
    {
        AfxInitExtensionModule(extensionDLL, hInstance);
        new CDynLinkLibrary(extensionDLL);
    }

    This dynamically loads the DLL. If we put some of this code into the EXE project like so:


    Code:
    HINSTANCE hDll2 = LoadLibrary(szFilename2);
    AfxInitExtensionModule(extensionDLL,hDll2);
    new CDynLinkLibrary(extensionDLL);
    After the AfxSetResourceHandle(hDll); //setting satellite DLL overriding EXE resources

    Originally, the EXE would be the resource container, but AfxSetResourceHandle(satelliteDLL) will set loaded DLL as default resource container, overriding the EXE like.

    We use the above extension DLL to chain (add-on) another resource DLL.

    The only issues now is freeing the library/memory..

  6. #6
    VictorN's Avatar
    VictorN is online now Super Moderator Power Poster
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    Re: HELP: how to load satellite DLL for a DLL

    There is FreeLibrary API to unload dll and free the memory.
    Victor Nijegorodov

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