c pointer, how to free it/them into a function

Question

This is my code:

#include 
#include 
#include 

void getinfo(unsigned int a, unsigned int b, char **pStr);

in         


        

Answer 1

This is more of a general C language advice than a specific answer, but it's too long to go in comment.

The usual way to write C in the presence of dynamic resource management is to goto suitable labels which are followed by the relevant deallocation calls:

int f(int n)
{
    void * p1, * p2, * p3;
    int result = -1;

    p1 = malloc(n);

    if (!p1) goto END0;
    if (n % 2) goto END1;

    p2 = malloc(3 * n);

    if (!p2) goto END1;
    if (n % 7 == 0) goto END2;

    p3 = malloc(7 * n + 8);

    if (!p3) goto END2;

    if (do_useful_stuff(p1, p2, p3) == -1) goto END3;
    result = compute_more_stuff(p1, p2, p3);

END3:
    free(p3);
END2:
    free(p2);
END1:
    free(p1);
END0:
    return result;
}

The alternative is to split up your code into very small functions that do only one thing at a time and handle resource allocation in an ad-hoc fashion:

int small_function(void ** p)
{
    void * q = malloc(13);

    if (some_init(&q) == -1)
    {
        free(q);    // ad-hoc exit management
        return -1;
    }

    int n = complex_computation(q);
    free(q);
    return n;
}