It seems much more plausible to me that the author does understand short-circuit evaluation, but did not feel like explaining it in such detail to satisfy the tedious pedantry of HN comments.
My experience with writing answers Stack Overflow is that people in the comments will always figure out a way to interpret an answer as being incorrect, and latch onto it.
There is a tradeoff between clarity and pedantry. You don’t want to simplify something too much where it is no longer insightful, and you don’t want to write something with irrelevant detail that obscures the point you are trying to make.
I really don't think the author is fluent in C. They consistently put semicolons after brackets, and they have off-by-1 errors in array indexing, etc (the first search_ok looks past the end of string; the second search_ok won't see ok in the string "ok"). That's part of why I read it that way.
My experience is that C programmers with many years of experience will still make off-by-one errors. Most of the examples have the correct bounds. The semicolons don’t belong but… so what?
If you wish to report errors to the author, there is an email address at the bottom:
> Please drop me email about bug(s) and/or suggestion(s):
My experience with writing answers Stack Overflow is that people in the comments will always figure out a way to interpret an answer as being incorrect, and latch onto it.
There is a tradeoff between clarity and pedantry. You don’t want to simplify something too much where it is no longer insightful, and you don’t want to write something with irrelevant detail that obscures the point you are trying to make.