error LNK2005: _DllMain@12 already defined in SPLibrSync.obj

This is a discussion on error LNK2005: _DllMain@12 already defined in SPLibrSync.obj within the C++ Programming forums, part of the General Programming Boards category; I have a C code files. I have to create a Win32 DLL using the .c and .h files. Now ...

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    error LNK2005: _DllMain@12 already defined in SPLibrSync.obj

    I have a C code files. I have to create a Win32 DLL using the .c and .h files. Now when i included this file one by one. Now i am getting the error as "error LNK2005: _DllMain@12 already defined in SPLibrSync.obj". Will anyone please come ahead and solve this problem. Please do the needful.

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    Its hard... But im here swgh's Avatar
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    It sounds like you have acidently included main twice in the project.
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    Hello Sir,

    I have gone through my code and no where i have double main statement.

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    What does the function definition look like?

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    and the hat of int overfl Salem's Avatar
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    Do you have code inside .h files?
    Do you #include source files inside other source files?

    Both of these poor practices will lead to multiple definitions at the linker, even if they only appear once in actual source code.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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    Quote Originally Posted by Laserve
    What does the function definition look like?
    the function defination looks like :

    Code:
    BOOL APIENTRY DllMain( HANDLE hModule, 
                           DWORD  ul_reason_for_call, 
                           LPVOID lpReserved
    					 )
    {
        switch (ul_reason_for_call)
    	{
    		case DLL_PROCESS_ATTACH:
    		case DLL_THREAD_ATTACH:
    		case DLL_THREAD_DETACH:
    		case DLL_PROCESS_DETACH:
    			break;
        }
        return TRUE;
    }

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    MFC killed my cat! manutd's Avatar
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    And how many times do you include this header file?
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  8. #8
    (?<!re)tired Mario F.'s Avatar
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    go to this source file, SPLibrSync. You have DllMain() defined there.

    Now, it can be either because it's actually coded in that file, because you are including the cpp file that defines it (never include cpp files), or you are including an header (.hpp or .h) file that has it defined (never define functions inside header files unless they are inline functions).

    Search for those three situations starting with SPLibrSync.cpp
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    The programmer comes home with 12 loaves of bread.


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