_beginthread when function has more than one parameter

This is a discussion on _beginthread when function has more than one parameter within the C Programming forums, part of the General Programming Boards category; I have been testing multithreading in windows. currently the function for the begin thread takes a single argument. I want ...

  1. #1
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    Question _beginthread when function has more than one parameter

    I have been testing multithreading in windows. currently the function for the begin thread takes a single argument.

    I want the addem function to take more that one function but I am unsure of the proper sytax.

    currently it looks like this:
    (process.h etc has been include, this version works)

    int addem(int);
    int main() {
    _beginthread((void (*)(void *))addem, 0, (void *)5000);
    /* Do Other Stuff */
    }
    .... etc

    I want addem to take two values:

    int addem(int, char *);

    The syntax of the _beginthread is very confusing, how do I pass two parameters to the addem function in the _beginthread? The documentation just says that the final parameter is *arglist? What is the sytax of the arglist and for that matter are any of the (void(*)(void *))'s part of some kind of function declaration?



    BYron
    Last edited by blundstrom; 10-03-2001 at 09:58 PM.

  2. #2
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    Smile

    u may change addem to:

    typedef struct{
    int Num;
    char* pBuf;
    }mystruct;

    void* addem(mystruct* );

  3. #3
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    Thumbs down Struct No Worky!!!

    I tried your suggestion, but struct and struct pointers cannot be converted to (void *), a least the compiler doesn't want to try and if I leave out the (void *) cast it won't link because of the struct then is an unresolved external symbol.

    _beginthread looks like thsI

    _beginthread(__cdecl *(void *)function_name, int, *arglist)
    Last edited by blundstrom; 10-04-2001 at 12:50 PM.

  4. #4
    Has a Masters in B.S.
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    this is how you do it

    Code:
    #include <stdio.h>
    #include <process.h>
    
    typedef struct ST{ 
        int num; 
        char* buf; 
    }thestruct; 
    
    void Addem(thestruct* );
    
    int main()
    {
        thestruct st;
        st.num = 6000;
        _beginthread((void(*)(void*))Addem,0,(void*)&st);
        getchar();    // freeze program so you can see output
    }
    
    void Addem(thestruct* s)
    {
        printf("%d\n",(thestruct*)(s)->num);
        _endthread();
    }
    Last edited by no-one; 10-04-2001 at 12:54 PM.
    ADVISORY: This users posts are rated CP-MA, for Mature Audiences only.

  5. #5
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    Post Kewl, Thanks!!! But, what about the fuction with multiple arguments!!!

    Thanks for the solution,

    but what about the if the function has multiple arguments.

    It is impossible?

  6. #6
    Has a Masters in B.S.
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    >but what about the if the function has multiple arguments.
    It is impossible? <

    its possible, but finiky and unreliable, most of the time it won't even work.

    and passing int values never seem to work.

    somebody else here may have a solution but as far as i know it dosn't work well.

    mainly because your trying to pass multiple values to a single void pointer, how can a pointer point to multiple values?
    Last edited by no-one; 10-04-2001 at 01:33 PM.
    ADVISORY: This users posts are rated CP-MA, for Mature Audiences only.

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