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0 pointsGroxx1mo ago0 comments

That's true for signed numbers too though? `int_min - 2 > int_min`

I agree they're a bit more error-prone in practice, but I suspect a huge part of that is because people are so used to signed numbers because they're usually the default (and thus most examples assume signed, if they handle extreme values correctly at all (much example code does not)). And, legitimately, zero is a more commonly-encountered value... but that can push errors to occur sooner, which is generally a desirable thing.

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4 comments · 2 top-level

oasisaimlessly1mo ago· 2 in thread

> That's true for signed numbers too though? `int_min - 2 > int_min`

No, that's undefined behavior in C, and if you care about correctness, you run at least your testsuite in CI with -ftrapv so it turns into an abort().

GroxxOP1mo ago

Which makes them even less safe than unsigned, where it is defined, yes? The optimizations that can lead to are incredibly hard to predict.

Besides, for safety there are much clearer options, like wrapping_add / saturating_add. Aborting is great as a safety tool though, agreed - it'd be nice if more code used it.

uecker1mo ago

You can have the trap during production, and then it is safer. If you need to catch the problem at run-time, there are checked integer options in C that you can use.

pron1mo ago

> That's true for signed numbers too though? `int_min - 2 > int_min`

As someone else already pointed out, that's undefined behaviour in C and C++ (in Java they wrap), but the more important point is that the vast majority of integers used in programs are much closer to zero than to int_min/max. Sizes of buffers etc. tend to be particularly small. There are, of course, overflow problems with signed integers, but they're not as common.

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