3 ms·

IB means the implementation has to fully document what it does. Evidently they didn't want to impose that requirement.

• aw1621107 4mo ago
  There's always unspecified behavior if documentation is considered to be too onerous.
• UncleMeat 4mo ago
  It also means that the behavior needs to be stable across time and that tools cannot report this behavior as a bug.
  • aw1621107 4mo ago
    > It also means that the behavior needs to be stable across time I don't think IB has to be stable over time? For instance, whether and which extended integer types exist is IB and that has definitely changed over time. > and that tools cannot report this behavior as a bug. It's absolutely possible to report IB as a bug (or even fully-specified behavior, as demonstrated by -fsanitize=unsigned-integer-overflow or -fsanitize=implicit-integer-conversion).
    • UncleMeat 4mo ago
      IB is something that developers can rely on. If it changes out from under you thats a bug.
      • aw1621107 3mo ago
        To the extent that implementations promise, sure. But that is beyond the scope of the standard.