Thread: How to loadlibrary from a new thread

  1. #1
    Registered User
    Join Date
    Apr 2010
    hellertown, pennsylvania

    How to loadlibrary from a new thread

    Hello everyone,

    I've searched the forum for an answer to my newbie question, but found nothing directly related to it...although lots of good stuff about DLL's.

    In my little program in the main() I successfully use LoadLibrary and GetProcAddress and call a couple of functions in a DLL. In short, the DLL works as such. Then, I CreateThread(...) and create a new thread. The function called by CreateThread attempts to do a LoadLibrary and GetProcAddress to the SAME DLL. Nothing happens. No error messages, no nothing. The function invoked by CreateThread gets to the line in which LoadLibrary is called and does nothing. Program exits without errors.

    The DLL itself has a BOOL WINAPI DllMain entry point with the "usual" DLL_PROCESS_ATTACH, etc. values in a switch block.

    It seems like what I'm trying to do should work, but it doesn't. I have zero tech support, and I'm out of ideas.

    Thanks for considering this problem.

    Regards to all,
    Mark Allyn

  2. #2
    Registered User
    Join Date
    Jan 2009
    Have you tried passing the address of the DLL that you got from the first LoadLibrary into the function that is being run by the new thread?

    DLLs are loaded into the address space of the entire process so you don't really need to call LoadLibrary again unless the main thread might unload the library before the second thread is done with it.

    Are you sure that the functions you're calling aren't working properly? Is there a reason that the program should stay open for longer than that?

  3. #3
    System Novice siavoshkc's Avatar
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    Jan 2006
    Isn't it a platform specific thread?
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  4. #4
    C++ Witch laserlight's Avatar
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    Moved to Windows Programming.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
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  5. #5
    train spotter
    Join Date
    Aug 2001
    near a computer
    What does GetLastError() return?

    Generally DDLs loaded at runtime (dynamically) should either;

    have global scope (loaded once and passed around as required)


    loaded, used and released as required.

    This depends on the requirements of the app and the DLL.

    Also IIRC once a process has called LoadLibrary() on a particular DLL (and so 'mapped' it) the DLLMain() will not get called again by the same process (until the DLL is unmapped with a call to FreeLibrary() ).
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