What's the proper use of printf to display pointers padded with 0s

Question

In C, I\'d like to use printf to display pointers, and so that they line up properly, I\'d like to pad them with 0s.

My guess was that the proper way to do this was:

Answer 1

Use:

#include 

printf("0x%016" PRIXPTR "\n", (uintptr_t) pointer);

Or use another variant of the macros from that header.

Also note that some implementations of printf() print a '0x' in front of the pointer; others do not (and both are correct according to the C standard).