Please help me find memory leaks

This is a discussion on Please help me find memory leaks within the C Programming forums, part of the General Programming Boards category; I'm new to C and learning about dynamic memory allocation, and I would like some help if possible. I am ...

  1. #1
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    Please help me find memory leaks

    I'm new to C and learning about dynamic memory allocation, and I would like some help if possible.
    I am getting memory leaks, but I am not sure precisely where. Whenever I call Resize_Hash_Table, then memory problems begin. I thought I was using free right, but once I get large files, such as data2.txt, then I get memory leak problems. A log of valgrind would be great.
    EDIT:
    Thanks, I got it working
    Last edited by Lechx; 04-24-2006 at 01:48 PM.

  2. #2
    and the hat of wrongness Salem's Avatar
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    Impatient aren't you?
    Function to check memory left from malloc and free?
    All of 9 hours passed.

    Have you done anything in that time? No one is going to compare your two massive posts just to find out.


    > if (HT->Size > HT->NumBuckets * RESIZERATIO)
    > Resize_Hash_Table(HT);
    Have you already gone off the end of the array when you do this?
    The tests for arrays are usually
    index < N
    index >= N

    > void *malloc(unsigned int);
    Include the correct header file (once), rather than prototype it yourself every time you use it.
    #include <stdlib.h>

    Also, all your other function prototypes should be at the start of the file, not listed in every single function which uses them.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  3. #3
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    Sorry, I tried to PM you to delete my other post, but when I try to PM it says I do not have user privledges. Is it possible for me to delete my other post?
    Last edited by Lechx; 04-24-2006 at 07:41 AM.

  4. #4
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    If you're using Linux, you might want to consider using something like efence.

    http://www.google.com/search?hl=en&i...=Google+Search
    Last edited by cdalten; 04-24-2006 at 07:51 AM.

  5. #5
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    I read some of your code.

    So . as told earlier. Function prototypes should be posted
    in the beging of the file.
    You don't need to prototype library functions like malloc, and
    you might get errors from doing it. Use include.

    In the fucntion Insert :
    Code:
          if (HT->Size > HT->NumBuckets * RESIZERATIO)
             Resize_Hash_Table(HT);
    Why are you resizing the hash table ?

    In the function Resize_Hash_Table
    Code:
    HT2.FreeLinks = NULL;
    You wasting a way what ever memory you had in HT.FreeLinks.
    Much more than that, while building the new hash table. You
    are coping data ! Why not just change the pointers ?


    last, I think you maybe you should read about hast tables.
    As far as I know, its an array of pointers. And each pointer,
    points to the beging of a linked list. In your program that will never happen.

    This as far as I got.

  6. #6
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    Talking

    Quote Originally Posted by dude543
    So . as told earlier. Function prototypes should be posted
    in the beging of the file.
    You don't need to prototype library functions like malloc, and
    you might get errors from doing it. Use include.

    In the fucntion Insert :
    Code:
          if (HT->Size > HT->NumBuckets * RESIZERATIO)
             Resize_Hash_Table(HT);
    Why are you resizing the hash table ?

    In the function Resize_Hash_Table
    Code:
    HT2.FreeLinks = NULL;
    You wasting a way what ever memory you had in HT.FreeLinks.
    Much more than that, while building the new hash table. You
    are coping data ! Why not just change the pointers ?


    last, I think you maybe you should read about hast tables.
    As far as I know, its an array of pointers. And each pointer,
    points to the beging of a linked list. In your program that will never happen.

    This as far as I got.
    Thanks for all the tips! I did what you said and changed pointers instead of re-creating a hash table. It works great now!!! I doubt i'll ever use this function in the real world, but now i'm going to start on learning garbage collection

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