Date:	Sat, 08 Mar 2003 11:41:52 +0200
From:	"Eli Zaretskii" <eliz AT elta DOT co DOT il>
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To:	rich AT phekda DOT freeserve DOT co DOT uk
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In-reply-to:	<3E69434C.B420FA9D@phekda.freeserve.co.uk> (message from Richard
	Dawe on Sat, 08 Mar 2003 01:11:40 +0000)
Subject:	Re: New POSIX: pwrite [PATCH]
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> Date: Sat, 08 Mar 2003 01:11:40 +0000
> From: Richard Dawe <rich AT phekda DOT freeserve DOT co DOT uk>
> 
> I thought we were talking about how to detect TTYs that have been redirected
> (aka piped), so that we can fail pwrite and set errno == ESPIPE.

As I wrote elsewhere in this thread, I don't see why should pwrite
fail in those cases.  I think it shouldn't: DOS doesn't have real
pipes.

> > Hmmm... probably.  The code in isatty.c looks suspect; it only returns
> > true if a device is both stdin *and* stdout.  It should probably also
> > just check for device vs file.
> 
> I see what you mean. Are all character devices TTYs?

I don't think that every character device should cause `isatty' return
a non-zero value.  Programs that want to detect character devices
should call `stat' and look at the mode bits.  `isatty' should IMHO
return non-zero only for terminal devices.

While the distinction might be very close to moot in DJGPP, it is IMHO
still an important distinction, even if only to avoid user confusion.
For example, consider the character-device interface presented by
memory managers such as EMM386 or QEMM, or by MSCDEX: it would confuse
the heck out of users if `isatty' returned non-zero for them.  I
think.

So I think we should first think whether there are good reasons to
modify `isatty' so it returns non-zero for every character device.

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