Question

I’m trying to send a pointer to function, but the pointer is part of an array of pointers

void func(A **pa)
{
     return;
}


A *pa;
pa=(A*)malloc(2*sizeof(A));

So, the first item in the array pa[0] is easy to send (because it is the place the pointer points to)

func(&pa);

But now I get stuck, how can I send the second item? pa[1]

I tried something like func(&pa + 1*sizeof(A));
but it didn’t seem to work.

Answer 1

You are looking for &pa[1]:

func (&pa[1]);   // call function with second element of pointer array

---

By the way, I can’t tell if you mean to allocate an array of only two pointers, but if you are, the malloc is in error. It should be

pa = malloc (2 * sizeof(A*));  // note the addition of * after "A"

What you are doing is allocating twice the size of an A, which conceivably could be thousands of bytes long. That much space is not needed for a pointer to such an object.

Also, in C, one need not—and should not—cast the return type of malloc().