for pre-ANSI C most of these questions are answered by "it depends on the compiler" which is why ANSI C happened. Of course the answer is still "it depends on the compiler" for this behavior, since it's not defined what it does in ANSI C, just that it's not portable to do it.
I remember working on a Fujitsu box in 1993, which used some sort of weird System V Unix with pre-ANSI C and weirdly abbreviated man pages in Engrish. (shudder) Yeah.