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carrayspointersfreevoid-pointers

How to free void array of void pointers?

I managed to narrow my problem to this code snippet:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main()
{
    void **arr;
    int max = 10; //tr = 0;
    int size = sizeof(int);

    arr = malloc(max*sizeof(void*));

    for (int i=0; i<=6; i++)
    {
        arr[i] = malloc(size);
        memcpy(arr+i, &i, size);
    }

    for (int i=0; i<=6; i++)
    {
        printf("%d ", *(int*)(arr + i));
    }

    free(arr[0]);
    free(arr[1]);

    free(arr);
    return 0;
}

It's ok when I free arr, and it's ok when I free arr[0]. But anything other than that I get a segfault.

Am I doing the allocations wrong? Or is it something else?

Solution

  • should be

    for (int i=0; i<=6; i++)
{
    arr[i] = malloc(size);
    memcpy(arr[i], &i, size);
}

for (int i=0; i<=6; i++)
{
    printf("%d ", *(int*)(arr[i]));
}