Doubt: File I/O and DLLs

This is a discussion on Doubt: File I/O and DLLs within the C Programming forums, part of the General Programming Boards category; Hello everybody! I'm a newbie on programming and I'm trying to create a routine to write some calculated variables on ...

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    Question Doubt: File I/O and DLLs

    Hello everybody!

    I'm a newbie on programming and I'm trying to create a routine to write some calculated variables on a text file. There is a lot of file I/O examples on the internet, and I've made some by myself (they work fine), but when I try to use them on a DLL, nothing happens, though the compilation runs successfully.

    Is there any mystery about File I/O and DLLs on C?

    Thanks in advance,

    Gabriel Casagrande

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    I don't get this question.
    Post code...
    ...and, C or C++?

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    I'm using this language to edit an open-source software, which has a graphical interface that uses an engine (a DLL made in C). This software is for hydraulic systems project. On my final thesis, I have to change the original water demand calculations of this model.

    So, I am trying to create a routine to write the variables on a text file and then, pass by pass, know if what I am calculating is correct or not.

    When I use the codes I created in a different project (a console application), everything runs fine: the text file is created, and the variables are written on the file. But, using the same code on the DLL, nothing happens.

    The code is:

    Code:
    void demands()
    
    {
        FILE *f;
        int i;
        f = fopen("demands.txt", "w");
        for (i=1; i<=Njuncs; i++)
       {
           fprintf(f, "%d %d/n", i, D[i]);
       }
       fclose(f);
    
    }
    Where D[i] is the demands array, calculated in other function. I've tried to run the code inside that function, but nothing happened either.

    Thanks,

    Gabriel

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    a guy with long hair Xupicor's Avatar
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    Are D and Njuncs global variables? Are you sure Njuncs has the value you think it has? It looks like you're using C and not C++, so this topic should be moved to appropriate section of the forum. Or, are you using C++?

    Also, newline char is '\n' and not "/n".

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    What does 'nothing happens' mean? Ensure your function is called properly. And check if the file is even created.

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    Quote Originally Posted by Xupicor View Post
    Are D and Njuncs global variables? Are you sure Njuncs has the value you think it has? It looks like you're using C and not C++, so this topic should be moved to appropriate section of the forum. Or, are you using C++?

    Also, newline char is '\n' and not "/n".
    Ops! Sorry, It's true, the topic is in the wrong section... I'm using C
    How could I move it to the right section?

    D[i] and Njuncs are global and I've tried to use this code inside the D[i] calculation routine. I guess everything's alright with Njuncs, but I'll look at this carefully.

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    Quote Originally Posted by kmdv View Post
    What does 'nothing happens' mean? Ensure your function is called properly. And check if the file is even created.
    I mean that the file is not created =)

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    C++ Witch laserlight's Avatar
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    Quote Originally Posted by gabrielksa
    Ops! Sorry, It's true, the topic is in the wrong section... I'm using C
    How could I move it to the right section?
    Moved to C programming forum.
    C + C++ Compiler: MinGW port of GCC
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