Converting a non-`void` pointer to `uintptr_t` and vice-versa

Question

There are two related C standard rules:

C99 standard, 6.3.2.3:

A pointer to void may be converted to or from a pointer to any i

Answer 1

I wouldn't risk it. The standard makes it abundantly clear what is allowed and what is not allowed.

Writing uintptr_t s = (uintptr_t)(void*)p; signals to a reader of your code that you know what you're doing.