# How is system specific code or code with undefined behavior treated, if not explicitely stated? [duplicate]

I'm asking this especially after I stumbled on this question myself when I got asked some minutes ago in a comment, if the include in my C code is really neccessary.

I answered that it is, since I need printf which would be implicitly declared if I didn't include the stdio.h, but that results in unspecified behavior.

(though I can't think of a case where it wouldn't work for that challange so one could argue...)

So are PCG's challenges by default required to be as portable as possible, or will I have succeded as soon I can verify, that there is a system where my golfed code succeeds the challange?

• I believe this recently ascked question answers your question as well. The conclusion was that an implementation, such as a specific compiler/platform combination, is sufficient to define a langauge. – isaacg Sep 4 '15 at 12:49