Does Standard define null pointer constant to have all bits set to zero?

Question

( I\'m quoting ISO/IEC 9899:201x )

Here we see that, integer constant expression has an integer type:

6.6 Constant expressions

6. An in

Answer 1

Does Standard define null pointer constant to have all bits set to zero?

No, it doesn't. No paragraph of the C Standard impose such a requirement.

void *p = 0;

p for example is a null pointer, but the Standard does not require that the object p must have all bit set.

For information the c-faq website mentions some systems with non-zero null pointer representations here: http://c-faq.com/null/machexamp.html