>> Садись 2
>> это решение комитета по стандартизации оставить детали реализации на усмотрение разработчиков компилятора.
> Чел, ты лучше сам сядь. Да выучи, чем отличается UB от implementation-defined
> behavior.

Ну, давай учить в_месте:

3.4.3

1 undefined behavior
behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which
this International Standard imposes no requirements

2 Note 1 to entry: Possible undefined behavior ranges from ignoring the situation completely with unpredictable results,
to behaving during translation or program execution in a documented manner characteristic of the environment (with or
without the issuance of a diagnostic message), to terminating a translation or execution (with the issuance of a diagnostic
message).

3 EXAMPLE An example of undefined behavior is the behavior on integer overflow.