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Comment by flohofwoe | Hacker News Reader

It would already help a lot when the C and C++ standards start to clean up the list of Undefined Behaviour (e.g. there's a lot of nonsense UB currently in the C standard which could easily become Defined Behaviour - like the "file doesn't end in a new-line character" thing):

https://gist.github.com/Earnestly/7c903f481ff9d29a3dd1

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The C committee is cleaning up a lot of UB (check https://www.open-std.org/jtc1/sc22/wg14/www/wg14_document_lo... for paper titles like "slaying earthly demons").

But don't misunderstand the goal of that: C and C++ will never get rid of UB. The result of dereferencing an invalid pointer is UB, will always remain UB, and really cannot be anything other than UB.

The easy cases like you cite are also those that don’t cause problems in practice. I’m not sure that would help all that much, other than to slightly reduce internet criticism.

Fixing easy cases makes the list shorter, so enables more focus on harder cases.

And it also signals that you actually do want to improve, just a little bit of boy scout rule goes a long way.

The issue is that the list is infinite (anything not specified is UB), so actually removing any finite amount of UB from the list won't make it shorter.

(only slightly tongue-in-cheek, I do believe that removing silly things is worthwhile).

The list of UB categories and rules is not infinite. The list of UB programs is, as is the list of all non UB programs.

It is not obvious to me that the list of categories is not infinite (unless the final category is "everything else" of course)

To be undefined behaviour, it must at least be valid syntax. The syntax is described in a finite document. Also it only gets executed by a finite machine, that has a finite number of finite descriptive documents.

The list of unspecified behaviour is infinite, but the list of undefined behaviour is well defined and finite ;)

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