ISO C requires:

        (1) "char" have at least 8 bits.
        (2) sizeof(char) == 1.
        (3) "int" be able to hold at least -32767..32767.
        (4) "long" be able to hold at least -2147483647..2147483647.
        (5) "int" be no bigger than "long".

There are other requirements, but these are the relevant ones.

John Payson writes:
> I personally find it offensive that most C compilers for the PIC
> (the only exception I know of is HiTech's) regard "int" as an 8-bit
> type and "long" as a 16-bit type.  Both of these definitions are
> clearly contrary to the C standard

Correct; rule (4) is violated, "long" is not big enough.

> (nb: a compiler I use on a different chip has both "char" and "int"
> as 16-bit types, and sizeof(char)==1, but _that_ is _allowable_ by
> the C standard).

Correct.

Martin Green writes:
> A 16 bit int is not part of the C standard.

An int that can represent -32767..32767 *is* part of the C standard.

Philip Restuccia writes:
> As someone else has already pointed out, the "C standard" does NOT
> define any particular sizes for ANY integral data types; they are
> platform-dependent.

K&R C did not define particular (minimum) sizes, but ANSI/ISO C
does.

Argh!  I see John Payson has followed up with an even more exhaustive
listing of the ANSI/ISO C requirements.  He covered them perfectly.
An excellent source book is Harbison & Steele's _C: A Reference
Manual_.  I worked on a C compiler on an unusual platform, and
having the actual rules (rather than the assumptions I'd carried
around with me from working on normal platforms) was a tremendous
help.

Brian