Visual C++ Problem?

This is a discussion on Visual C++ Problem? within the Windows Programming forums, part of the Platform Specific Boards category; I am trying to use the _beginthreadex function instead of CreateThread (because I am more comfortable using older C functions), ...

  1. #1
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    Visual C++ Problem?

    I am trying to use the _beginthreadex function instead of CreateThread (because I am more comfortable using older C functions), but even when I include <process.h> I get "...cpp(764) : error C2065: '_beginthreadex' : undeclared identifier"

    So, I added the prototype myself:
    unsigned long __cdecl _beginthreadex(void *, unsigned, unsigned (__stdcall *) (void *), void *, unsigned, unsigned *);

    but then I started receiving...
    ...obj : error LNK2001: unresolved external symbol "unsigned long __cdecl _beginthreadex(void *,unsigned int,unsigned int (__stdcall*)(void *),void *,unsigned int,unsigned int *)" (?_beginthreadex@@YAKPAXIP6GI0@Z0IPAI@Z)

    So, of course, I linked LIBCMT.LIB and also tried MSVCRT.LIB, but i still received the same "unresolved external symbol" error.

    Is there something else I need to do?? (I am using Visual C++ 6.0 -- this is a non-MFC app I am working on)

    Thanks
    Last edited by Echidna; 04-09-2002 at 11:48 PM.

  2. #2
    train spotter
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    MSVC v6 help says _beginthreadex() is not supported / compatible for WIN98 or WIN2000 (only WIN95 and NT).
    "Man alone suffers so excruciatingly in the world that he was compelled to invent laughter."
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  3. #3
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    Thanks Novacain!

    I don't have the MSDN help files since I just borrowed the Visual C++ CD from a friend...

    I will have to use CreateThread() then...I was trying to avoid that since it leaks memory when used with old C functions

    One problem though, I don't know an API that can work like the C function int tolower(int); Any suggestions??????

    Thank you

  4. #4
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    write your own?!

    something like

    Code:
    int MyToLower(char* string)
    {
        int len = ::lstrlen(string);
        for(int i = 0; i < len; i++)
        {
            if(string[i] >= 'A' && string[i] <= 'Z')
            {
                string[i] -= 32;
            }
        }
    
       return(1);
    }
    note: I didn't compile this code, I just wanted to give you the idea.

    good luck!
    U.
    Quidquid latine dictum sit, altum sonatur.
    Whatever is said in Latin sounds profound.

  5. #5
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    Uraldor Wrote:
    <<<write your own?!
    something like
    code:
    int MyToLower(char* string)
    {
    int len = ::lstrlen(string);
    for(int i = 0; i < len; i++)
    {
    if(string[i] >= 'A' && string[i] <= 'Z')
    {
    string[i] -= 32;
    }
    }

    return(1);
    }>>>

    Well, I could of done that myself (better yet, I could have used CharToLower), but that is not what the function tolower does. I included the prototype in my last post: int tolower(int);
    An int, not a char* is passed to the function. Quite frankly, I don't know how it works. And since I am looking for a replacement...

    tolower is able to handle this type of conditional statement:

    char *Read;
    int ArrayElement;
    .
    .
    .
    if(tolower(Read[ArrayElement]) == 'i')
    {
    // Do this
    }

    I was wondering if there is an API that does the same thing.

    See what I mean?

    Thanks

  6. #6
    It's full of stars adrianxw's Avatar
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    >>>
    MSVC v6 help says _beginthreadex() is not supported / compatible for WIN98 or WIN2000 (only WIN95 and NT).
    <<<

    I'd never noticed that, so intrigued, I tried a little test...

    Code:
    #include <windows.h>
    #include <stdio.h>
    #include <process.h>
    
    unsigned Counter;
    
    unsigned __stdcall SecondThreadFunc( void* pArguments )
    {
        printf( "i tråd...\n" );
        while ( Counter < 1000000 )
            Counter++;
    
        _endthreadex( 0 );
        return 0;
    }
    
    void main()
    {
        HANDLE hThread;
        unsigned threadID;
    
        printf( "lave tråd...\n" );
        hThread = (HANDLE)_beginthreadex( NULL, 0, &SecondThreadFunc, NULL, 0,
            &threadID );
        WaitForSingleObject( hThread, INFINITE );
        printf( "tælle skulle være 1000000; er -> %d\n", Counter );
        CloseHandle( hThread );
    }
    ... works fine with Win 2000, VC 6.0 Pro.

    I bet you haven't changed your project settings to multithreaded...
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

  7. #7
    the hat of redundancy hat nvoigt's Avatar
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    >I don't know an API that can work like
    >the C function int tolower(int);

    >Any suggestions??????

    Use the C function ? Who said you may not use it ?
    hth
    -nv

    She was so Blonde, she spent 20 minutes looking at the orange juice can because it said "Concentrate."

    When in doubt, read the FAQ.
    Then ask a smart question.

  8. #8
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    nvoigt...wrote, "Use the C function ? Who said you may not use it ?"

    "A thread that uses functions from the C run-time libraries should use the beginthread and endthread C run-time functions for thread management rather than CreateThread and ExitThread. Failure to do so results in small memory leaks when ExitThread is called. "

    http://students.cs.byu.edu/~cs345ta/...helpfiles.html

    Is this still the case???? I assume it is

    adrianxw wrote, "... works fine with Win 2000, VC 6.0 Pro.
    I bet you haven't changed your project settings to multithreaded..."

    Under Projects - Settings (or Alt F7) - Link - Object/library modules: I added the MSVCRT.LIB (and also tried LIBCMT.LIB) but I don't think that is what you meant ...So I will search the MSDN home page...

    Thanks for the help

    By the way, I meant CharLower not CharToLower :-p

    Later on...

    Ahhh...I found it...
    "To find these options in the development environment, click Settings on the Project menu. Then click the C/C++ tab, and click Code Generation in the Category box. See the Use Run-Time Library drop-down box. "

    http://msdn.microsoft.com/library/de...t.2c_2f.ld.asp

    http://msdn.microsoft.com/library/de...d_programs.asp

    Thanks Adrianxw, I had no idea
    Last edited by Echidna; 04-11-2002 at 12:36 PM.

  9. #9
    It's full of stars adrianxw's Avatar
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    >>> Is this still the case???? I assume it is

    I had a little discussion with Sunlight about this, and whilst he decided in theory it should no longer be necessary, we agreed that we would both continue using beginthreadex().

    >>> Ahhh...I found it...

    Sorry, I assumed you knew and had simply forgotten to do it. I should have given the sequence with my message.

    Glad your okay now.
    Wave upon wave of demented avengers march cheerfully out of obscurity unto the dream.

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