[doc] Size of IV & UV in perlguts & perl.h

[FGasper]

Where

perlguts describes IV as:

guaranteed to be large enough to hold a pointer (as well as an integer)

… which sounds a lot like the description of intmax_t:

A signed integer type capable of representing any value of any signed integer type.

These sound like system-wide things, but in actual implementation the size of IV and UV vary with Perl’s configuration.

Should these docs be amended to stipulate that it’s not about what the platform supports, but what Perl is configured for?

[tonycoz]

maybe it could also have "but may be larger, depending on how perl is configured."

[khwilliamson]

I think an IV should in fact be as large as required for a pointer to fit in it. Looking at Configure, I don't see anything that forces that. Am I wrong?