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A comment on Ask HN: Good practices for my first C project. Parent comment

Re:Ask HN: Good practices for my first C project by jcranmer on Wednesday October 18, 2023 @04:55PM (#37934640)
It is best not to try to roll your own checked arithmetic. Your compiler already has an implementation, that will likely compile down to "check the overflow flag in hardware", and carries 0 risk of undefined behavior. Why not use it?

("It's not portable" is a reason that will cease to be true shortly--as mentioned, C23 added checked overflow functions.)

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Re:Ask HN: Good practices for my first C project by gavinhoward on Wednesday October 18, 2023 @05:02PM (#37934717)
Because I want to stay on C11.

> Your compiler already has an implementation

That's a big assumption that is not true on all compilers I want to target.

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Re:Ask HN: Good practices for my first C project by yjftsjthsd-h on Thursday October 19, 2023 @12:13AM (#37938293)
> ("It's not portable" is a reason that will cease to be true shortly--as mentioned, C23 added checked overflow functions.)

So in practice, today, it's not portable and won't be for a while (even when it's released into compilers, it'll take time for those new versions to trickle into the ecosystem), which is a compelling argument against using it.

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