Modifying variable from external function

This is a discussion on Modifying variable from external function within the C Programming forums, part of the General Programming Boards category; Hi. I'm sure this has been asked before, but I couldn't find an answer, so I'll just ask again: I ...

  1. #1
    Registered User haifisch's Avatar
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    Question Modifying variable from external function[SOLVED]

    Hi. I'm sure this has been asked before, but I couldn't find an answer, so I'll just ask again:

    I have two separate modules:

    Code:
    mod1.c
    
    f2(int *value) {
    g1(value);
    }
    
    f1() {
    int value;
    f2(&value);
    }
    
    mod2.c
    
    g1(int *value) {
    if(something)  *value--;
    }
    If I printf *value in g1, it decrements correctly. However, when g1 returns to f1, value remains unchanged.

    I'm just not seeing it at the moment what I'm missing, so I'm about to 'give up' and just use "extern int value;" in mod2, its just that I'd like to get this working by 'reference'.

    Any help much appreciated
    Last edited by haifisch; 05-11-2010 at 06:02 AM.

  2. #2
    and the Hat of Guessing tabstop's Avatar
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    It would probably help to do
    Code:
    void g1(int *value) {
         (*value)--;
    }
    Assuming you mean to decrement the value pointed at and not the pointer itself.

  3. #3
    Registered User haifisch's Avatar
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    Oh my god

    I'm absolutely sure I tried that at some point...

    Well thanks alot

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