Clarify (un)signed-ness of pointers for comparisons

[gamozolabs]

It seems currently pointer comparisons, ala. (foo as *const u32) > (bar as *const u32). Emits an unsigned comparison. I looked a little bit to see if this was documented somewhere and I didn't see anything super obvious.

Is this something that is defined behavior, and if it is, could we clarify it in the primitive pointer type documentation? This can be relevant especially in many kernel designs when there are "negative" addresses in the kernel and "positive" in user-space.

Thanks!
-B

[RalfJung]

Yes, pointers are definitely treated as unsigned integers for inequality comparisons. There is no such thing as a "negative address", just an address >= 0xF0000000[00000000].