Re: text vs. binary [Re: more gcc warnings]

[Paul Eggert]

address@hidden (Eric Blake) writes:

> http://lists.gnu.org/archive/html/bug-coreutils/2005-05/msg00136.html

I just looked at that, and don't really follow all the DOS stuff, but
have these comments anyway:

> cat - POSIX requires binary input and output, and this already has -B option 
> to fine-tune mode

I've removed -B.  It didn't really work on DOS, as far as I could see.
And it wasn't portable (it didn't work on GNU/Linux).

> head - POSIX requires text input, but compare to tail -c on binary input

Currently "head" runs in binary mode (which means, in DOS, that it
uses binary mode except if stdin/stdout is a tty).

> nohup - POSIX requires that stdout from utility may to go to nohup.out, so
> nohup.out should probably be opened in same mode as nohup's stdout (if it
> exists)

nohup.out is currently opened in text mode.  Let's just leave that
alone, unless someone really needs it.  (I doubt whether they will.)

> I've thought
> more about fcntl(fd, F_SETFL, flags), where the nice gnulib behavior
> would be:
> neither O_BINARY nor O_TEXT: leave mode unchanged
> O_BINARY: if not tty, force binary mode
> O_TEXT: if not tty, force text mode
> O_BINARY | O_TEXT: if not tty, swap mode

My kneejerk reaction is that sounds pretty confusing.  But perhaps I
don't see the application area.

>> and have a wrapper on MS-DOS that defines freopen to not do anything
>> if the first argument is NULL, the second ends in "b", and the third a
>> standard tty?
>
> Since POSIX states that "w+b" and "wb+" are synonyms, for example,

OK, use 'contains "b"' instead of 'ends in "b"'.

> I'd like to see a deprecation period rather than outright removal,
> where -B is undocumented, and using it evokes a warning but
> is otherwise a no-op (rather than a fatal unrecognized option).

You could talk me into that, yes.

> Are there non-standard hosts out there that don't treat "ab" as
> a synonym to "a" per POSIX

Yes.  At least, such hosts used to exist.  Maybe we needn't worry
about them now.  I suppose I can rip out the (O_BINARY ? "rb" : r")
stuff.  (Though this does save a byte on POSIX hosts.  :-)