Thread

1. BobbyTables2 · 1789744507 · focus · HN ↗

   TLDR: For almost 1/6 of a century, the C++ standards broke the simplest infinite loop and only just recently fixed it.

   Idiots!

   Don’t they really that people write real programs to solve real problems? This isn’t a theoretical academic exercise!

   1. Sharlin · 1789745143 · focus · HN ↗

      The argument is that an infinite loop without side effects isn't a real program. It's not useful for anything except wasting cycles.

      1. nh2 · 1789746338 · focus · HN ↗

         Of course the infinite loop should run as expected.

         It breaks the most fundamental debugging expectations (such as "delete code until problem disappears") if the fundamental, minimal building blocks of a language, when on their own, do random rubbish.

         To understand a program that does something, better first understand a program that does nothing.

         As a fan of sensible analogies:

         You put a salad bowl with vinegar into the fridge and notice that when you do that, the fridge stinks afterwards. You try again without the vinegar, then without the salad. In C++ world, upon receiving the empty bowl, the fridge detonates ("it is not useful"), blowing up your house. That is not OK.

         1. Jaxan · 1789746850 · focus · HN ↗

            But if you program a for loop computing the sum from 1 to n, this also gets replaced by a constant (unless you build in debug mode). Why would an empty loop be different?

            1. vlovich123 · 1789748471 · focus · HN ↗

               I think the argument is that the equivalent of an infinite loop would be a halt / abort instruction, not a complete removal of the loop and continue running anything else.

               1. rcxdude · 1789750194 · focus · HN ↗

                  Not necessarily what you want in that case either: it's a common pattern in cases where you want the system to halt until you can attach a debugger to inspect the state. A halt/abort instruction that trashes that state would be undesirable (some CPUs have an instruction that is equivalent, but many do not, after all, why bother if you can just write an infinite do-nothing loop?).

                  1. vlovich123 · 1789838882 · focus · HN ↗

                     A halt instruction is probably the appropriate representation for an infinite loop - the process gets stuck same as the infinite loop without proceeding. Abort is the instruction you want unreachable() to compile down into. It wasn’t an either or but both depending on the specific behavior you want.

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