modifying double pointer to an integer array

Question

I have a pointer to an int *array, I allocated it and then pass it to a function in order to fill in the elements of the array.

void function(int **arr);

int main()
{
    int *array;
    array=calloc(4, sizeof(int));
    function(&array);
    return0;
}


void function(int **arr)
{
    int *tmp;
    tmp=calloc(4, sizeof(int));
    tmp[0]=1;
    tmp[1]=2;
    tmp[2]=3;
    tmp[3]=4;
}

I want to assign tmp to arr. How can I do it?

Answer 1

You don't need to calloc array in main, first of all. It's a pointer and all you need to do is assign tmp to it. Here's how:

void function(int **arr);

int main()
{
    int *array;
    size_t i;

    function(&array);
    // do stuff with array
    for (i = 0; i < 4; i++)
    {
        printf("%d\n", array[i]);
    }
    // then clean up
    free(array);

    return 0;
}


void function(int **arr)
{
    int *tmp;
    tmp=calloc(4, sizeof(int));
    tmp[0]=1;
    tmp[1]=2;
    tmp[2]=3;
    tmp[3]=4;

    *arr = tmp;
}