linking to my own DLL

This is a discussion on linking to my own DLL within the C++ Programming forums, part of the General Programming Boards category; Oddly, I've always linked to other peoples DLLs and never my own. Now, I want to link to my own ...

  1. #1
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    linking to my own DLL

    Oddly, I've always linked to other peoples DLLs and never my own. Now, I want to link to my own DLL, and I don't know why I can't.

    I created the DLL with code::blocks and I'm linking to the .a file code::blocks outputs. I also have a header with all the functions the DLL has. The functions are showing up in the auto complete, but when I try to compile, any function in the DLL gives an error saying that it was not declared.

    What do I need to do to get this working?

  2. #2
    Banned master5001's Avatar
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    Code::blocks probably gets the prototypes from the header, so that is trivial information. Are your exports done properly? Is it a run-time error, or a linker error?

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    I get: "ld.exe cannot find -l"nameoflib.

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    what is the name of your .a file?

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    libYsound.a

  6. #6
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    You need to be doing -lYsound. I am not sure how you specifically tell Code::blocks what which library to link in. But on whatever menu just tell it Ysound, not some exact file name.

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    It says the same thing. "ld.exe cannot find -lYsound." Do I have to have a lib file? All the other DLLs need to link to .libs, but Code::blocks doesn't give .lib files with the DLLs it compiles.

  8. #8
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    It could be a .lib. Or it could be a .a. They are funcitonally the same thing. Check your library include paths. What compiler are you running? gcc?

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    It is linking to the file that I want and including the header that I want. I'm using GCC.

    Am I doing something wrong in the DLL?

    Code:
    // dll cpp file
    #define DLLEXPORT extern "C" __declspec(dllexport)
    DLLEXPORT int foo(){ return 1; }
    Code:
    // header
    int foo();

  10. #10
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    Ah ok. You need to move that #define to your header and put the DLLEXPORT in the prototype.

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    Hm, I figured I probably did something wrong. However, it still cannot find -lYsound. I think I need a lib file.

  12. #12
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    ok... then rename your .a file to .lib. If that will make you happy Just don't forget to change your header to

    Code:
    #ifdef DLL_BUILD
    #  define DLLEXPORT extern "C" __declspec(dllexport)
    #else
    #  define DLLEXPORT extern "C" __declspec(dllimport)
    #endif
    
    DLLEXPORT int foo();

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    I'm still getting the same error. I get this any time I try to link to a dll I compiled with code::blocks to another project I'm compiling in code::blocks. Do I need to link to anything else other than that lib file?

  14. #14
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    Ok lets be PERFECTLY straight on this.

    When you build the DLL you need to put -DDLL_BUILD=1 in your command line. When you are building your project that uses the DLL, you do not put that.

    You probably need to recompile your DLL.

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    Well, it is working now, but I don't know why. I originally moved the files from where code::blocks had compiled them to the directory of the DLL I am currently working on. When I linked to the file there it couldn't find it. I moved them back to where code::blocks compiled it and linked to it from there and it worked. 0.o

    Thank you.

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