CODEWITHSUNDEEP
cmemory-leaks
Сергей Волков
Сергей Волков

Reputation: 35

Why is memory leaking in this code?

I'm a newbie in C and I have memory leak in my program. 

static int MT_reduce(MT_table** MT)
{
    MT_table* newMT = new_MT((*MT)->argc);

    /// fill data in the newMT ////

    if(isReduced == 1 && newMT->size > 0)    
    {
        MT_free(*MT);
        *MT = newMT;
    }

    return isReduced;
}

In other place I call this procedure:

    while(MT_reduce(&MT)==1);

I'm freeing old resources before assigning to MT the address of newMT, but why do I get a memory leak? How I can replace MT with newMT without leaking memory?

Upvotes: 0

Views: 119

Answers (1)

Ivaylo Strandjev
Ivaylo Strandjev

Reputation: 70939

In order to avoid memory leak you should edit the code in the following manner:

static int MT_reduce(MT_table** MT)
{
    MT_table* newMT = new_MT((*MT)->argc);

    /// fill data in the newMT ////

    if(isReduced == 1 && newMT->size > 0)    
    {
        MT_free(*MT);
        *MT = newMT;
    } else {
        MT_free(newMT);
    }

    return isReduced;
}

You should always free newMT even when you do not copy it.

Upvotes: 5

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