Pointers to objects or functions of the same type are equal if and only if in they are both NULL:
int *p1 = NULL, p2 = NULL;
bool equal = (p1==p2); //true
Or if they point to the same object:
char * pc1 = &c;
char * pc2 = &c;
equal = (pc1 == pc2); // true
Additionally, pointers are equal if they point one position past the end of the same array.