3 ms·

Is it that unusual? I've seen undefined behavior be specifically mentioned in both the Java and CLR standards. Rust's (admittedly squishy) "reference" also spec

Is it that unusual? I've seen undefined behavior be specifically mentioned in both the Java and CLR standards. Rust's (admittedly squishy) "reference" also specifies a lot of behavior as undefined explicitly (along with a general "if you break mandated invariants behavior is undefined").

steveklabnik 10y ago
In Rust's case, this is limited to unsafe code, at least; safe code should not have UB. (Though, IIRC there is one case right now, but that's a bug) UB is basically "breaking the invariants safe code expects." Overflow is an example of something that's not UB in Rust, for example. (It's a "program error" and well-defined as two's compliment wrapping.)