I was stung by not knowing this here.
Jokes apart, I'd be very useful if that info bar was provided. All lines end with \n?
4 lines, showing 4 (POSIX-compliant file)
As before, but the last line has no line terminator?
4 lines, showing 4 (non-POSIX-compliant file)
All lines end with \r\n except the last?
4 lines, showing 4 (typical Windows file)
Some lines end with \n other with \r\n?
4 lines, showing 4 (file with Windows and Unix mixed line endings)
All other cases?
Something like this I guess can be easily handled by having some function return an enum telling which case it is.