https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96042
--- Comment #2 from gcc-bugs at marehr dot dialup.fu-berlin.de --- I think this is too easy to say that this is not a "bug", we can also weaken the terminology and say "potential-inconsistency". Technically you are right, but only because there seems to be a specific "exception" for the implementation does not mean that this is the right thing to do. <unhappy-end-user - ignore this> I personally don't understand why the standard allows exceptions outside it's echo-system, I guess the stdlib implementers understand the subject better when forming the standard, and are lobbing harder for their necessities which is sometimes different from the needs / expectation of the end-user. </unhappy-end-user- ignore this> Can you help me figure out in which cases `-std=c++2a` would produce this type? Or asked differently: In which cases, other than this, do I encounter a `__int128` from using only types and functions defined in the standard? I have the feeling from your answer that this type is an everyday type. Looking at https://eel.is/c++draft/range.iota#view-1, and if I read it correctly, this is case 3: > Otherwise, IOTA-DIFF-T(W) is an unspecified signed-integer-like type > ([iterator.concept.winc]) of width not less than the width of W. > > [Note: It is unspecified whether this type satisfies > weakly_Âincrementable. — end note] It means it would be totally fine to return the signed version of `size_t`, because it has at least the same width. (This would be a valid option, too) Thank you for your time!
