Callback functions from dll

This is a discussion on Callback functions from dll within the Windows Programming forums, part of the Platform Specific Boards category; Hi. I've been trying to load a function from a dll, what I did was this: Code: typedef LRESULT (CALLBACK ...

  1. #1
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    Question Callback functions from dll

    Hi.

    I've been trying to load a function from a dll, what I did was this:

    Code:
    typedef LRESULT (CALLBACK *pfKeyProc)(int code, WPARAM wParam, LPARAM lParam);
    HINSTANCE dll = LoadLibrary(someLib.dll);
    pfKeyProc pfKey;
    pfKey = (pfKeyProc)GetProcAddress((HMODULE)(dll), "KeyboardProc");
    And the definition in the .dll looked like this :
    Code:
    extern "C" __declspec(dllexport) LRESULT CALLBACK KeyboardProc(int code, WPARAM wParam, LPARAM lParam);
    It didn't load correctly, but if I removed CALLBACK from the definition in the .dll it did. Should I define my typedef in some other way or could I just omit 'CALLBACK' from the defintion ?
    (Or am I doing it all wrong ?)
    Using : MSVS .NET 2003
    OS : Windows XP

  2. #2
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    One possible solution is to replace CALLBACK with __stdcall.

    Kuphryn

  3. #3
    Yes, my avatar is stolen anonytmouse's Avatar
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    Why can't I GetProcAddress a function I dllexport'ed?

    You need to compile your DLL with a DEF file. Otherwise, function names will be decorated.

    Alternatively, you can use (not preferred, processor dependent):
    Code:
    pfKey = (pfKeyProc) GetProcAddress(dll, "_KeyboardProc@12");

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