http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49595
--- Comment #3 from brian m. carlson <sandals at crustytoothpaste dot net> 2011-06-30 18:12:39 UTC --- (In reply to comment #2) > sizeof(intmax_t) is fixed by various LP64 ABIs and cannot be changed That does sound potentially problematic. I don't see how that solves the standard conformance issue, though. If intmax_t cannot be changed, then I suppose the only appropriate behavior is not to provide any integer types larger than intmax_t with -std=c99. > I believe the stock answer is that __int128 is not a C99 extended integer > type, > so isn't one of the types that intmax_t can represent the value of There are five *standard signed integer types*.... There may also be *implementation-defined extended signed integer types*. The standard and extended signed integer types are collectively called *signed integer types*. Since the standard specifies intmax_t in terms of a "signed integer type", it therefore includes any implementation-defined extended signed integer types, including __int128_t.
