What does malloc(0) return?

What does malloc(0) return?

Would the answer be same for realloc(malloc(0),0)?

#include<stdio.h>
#include<malloc.h>
int main()
{
        printf("%p\n", malloc(0));
        printf("%p\n", realloc(malloc(0), 0));
        return 0;
}

Output from Linux GCC:

manav@manav-workstation:~$ gcc -Wall mal.c
manav@manav-workstation:~$ ./a.out
0x9363008
(nil)
manav@manav-workstation:~$

The output keep changing everytime for malloc(0). Is this a standard answer? And why would anyone be interested in getting such a pointer, other than academic research?

EDIT:

If malloc(0) returns dummy pointer, then how does following works:

int main()
{
    void *ptr = malloc(0);
    printf("%p\n", realloc(ptr, 1024));
    return 0;
}

EDIT:

The following code outputs "possible" for every iteration. Why should it not fail ?

#include<stdio.h>
#include<malloc.h>
int main()
{

        int i;
        void *ptr;
        printf("Testing using BRUTE FORCE\n");
        for (i=0; i<65000; i++)
        {
                ptr = malloc(0);
                if (ptr == realloc(ptr, 1024))
                        printf("Iteration %d: possible\n", i);
                else
                {
                        printf("Failed for iteration %d\n", i);
                        break;
                }
        }
        return 0;
}