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Perhaps we're not in a discussion that's worth continuing, but I'm talking about programming language design. There are languages with UB, and there are languag

• flohofwoe 2y ago
  Maybe from your point of view. But from elsewhere UB can be a useful tool because it allows wiggle room for compilers to support a wide range of platforms without sacrificing efficiency. It doesn't have to be as crazy as in modern C/C++ compilers, but some sane UB definitely makes sense (even Rust has that inside unsafe blocks). One could also argue that most UB in C/C++ should actually be IB, but that's a different discussion.
  • tialaramex 2y ago
    This "Wiggle room" would be at most implementation defined and in some cases just unspecified values, these probably aren't desirable but yes they're less dangerous than UB. Rust has UB if you don't obey the rules (Safe Rust doesn't because the rules are not your responsibility in Safe Rust, the unsafe superpowers allow you to do things the enforcement can't check but now all rules are your responsibility) but it's not somehow magically "more sane" than C++ it's ultimately lowering to the same LLVM IR that Clang uses. It's tolerable because you're only confronting the risk when you explicitly choose to do so. If you don't need to squeeze that last few drops of performance you can leave it. If you don't have the confidence, if your experts are too busy to review it, if you haven't had a proper night's sleep, you can write safe Rust today.