void ** equivalent to void * return?

Question

    void * alligned_malloc(size_t bytes , uint16_t allign)
{

    uint16_t offset = allign - 1 + sizeof(void*);

    void* p1 = malloc(offset + bytes);
    void**p2 = (void**)(((size_t)p1+offset) & ~(allign - 1));
    p2[-1] = p1;

    return p2; // Why is this correct ? should not the return be p2[0] as it is     returning void**

}

Please help me understand this modified malloc how is void** equivalent to void * return in this code ?

Answer 1

Any kind of pointer can be implicitly converted to a void *, including a pointer to a void *, aka void **.