Re:Initialization in C++ is Seriously Bonkers
by MaxBarraclough on Saturday January 05, 2019 @07:38PM
(#18835465)
Your first points are well taken. From a quick googling you're right about the way the spec phrases it. It is, of course, terribly precise about under what circumstances UB occurs - https://stackoverflow.com/a/23429477/
> I stayed away from using the term “undefined behavior” because I’ve had a lot of problems in the past with students believing undefined behavior means “but it works [...]
Seems to me that developing a due terror of UB is vital to having a basic understanding of C as a programming language * , and beyond that, it's vital to appreciating what C is.
As well as being a considerable practical headache (it's not a compiler bug, it's UB going haywire), it's one of the major differences between C and, say, Java (alongside the way C types are not portable, etc). I'd say it deserves some emphasis as a basic principle.
* I suspect some theorists would contend that, strictly speaking, C programs aren't programs, and C isn't a programming language. Programs are, theoretically, meant to unambiguously map inputs to outputs. C is not unambiguous. But, needless to say, I digress.
> I stayed away from using the term “undefined behavior” because I’ve had a lot of problems in the past with students believing undefined behavior means “but it works [...]
Seems to me that developing a due terror of UB is vital to having a basic understanding of C as a programming language * , and beyond that, it's vital to appreciating what C is.
As well as being a considerable practical headache (it's not a compiler bug, it's UB going haywire), it's one of the major differences between C and, say, Java (alongside the way C types are not portable, etc). I'd say it deserves some emphasis as a basic principle.
* I suspect some theorists would contend that, strictly speaking, C programs aren't programs, and C isn't a programming language. Programs are, theoretically, meant to unambiguously map inputs to outputs. C is not unambiguous. But, needless to say, I digress.