Why is my pointer not null after free?

Question

void getFree(void *ptr)
{
    if(ptr != NULL)
    {
        free(ptr);
        ptr = NULL;
    }
    return;
}
int main()
{
char *a;
a=malloc(10);
getFree(a);
if(a==         


        

Answer 1

You are passing the pointer By value.. (By default C passes the argument by value) which means you are updating the copy only ..not the real location..for that you might need to use pointer to pointer in C

void getFree(void **ptr)
{

    if(*ptr != NULL)
    {
        free(*ptr);
        *ptr = NULL;
    }

    return;
}