Hacker News Reader

Notably, the C standard does have an undefined behavior annex, Annex J.2, since C99. It's not mentioned in the post, and this omission in tandem with repeated usage of "C and C++" at various points might suggest otherwise to some people.

View on HN

And C has a UB study group and we are working on a technical rapport that in great detail describes how UB works in C, and a comprehensive list of sample code for all known UB.

Is there hope that we could some day achieve an exhaustive lists of all undefined behavior that C programmers need to be aware of?

I realize no one really knows today, but is there a path?

No. It would require listing not just every place the standard states undefined behavior is the result, but also every corner case not covered by the spec, or that is under-specified. It’s possible to document known instances, but never to document all possible sources of undefined or unspecified behavior.

Thw C standard has a list of all known UBs. We don't know if the list is complete, because the C standard makes anything not defined by omission UB, so its possible to discover new UB. The language is however pretty thoroughly explored.

Reply on news.ycombinator.com