[Tim]

On reading, libc usually takes care of what's needed, and what remains is to check for stray '\r' characters that stdio glossed over.

[Jack Jansen]

This'll work for Unix and PC conventions, but not for the Mac. Mac end of line is \r, so reading a line from a mac file on unix will give you the whole file.

I don't see how. Did you look at the code I posted? It treats '\r' the same as '\n', except that when it sees an '\r' it eats a following '\n' (if any) too, and replaces the '\r' with '\n' regardless. Maybe you're missing that Python reads lines one character at a time? So e.g. the behavior of the platform libc fgets is irrelevant.