termios & non-blocking I/O

[Yar Tikhiy]

On Tue, Apr 08, 2003 at 10:17:08PM +0400, Andrey A. Chernov wrote:
> On Tue, Apr 08, 2003 at 20:46:14 +0400, Yar Tikhiy wrote:
> > While not in disagreement with POSIX[1], such a behaviour has at
> > least one unwelcome consequence:  If a program has been compiled
> > with ``-pthread'', the TIME counter won't work on terminal descriptors
> > that are in blocking mode from the program's point of view -- read(2)
> > will instantly return 0 on them.  That is because the following
> > scenario will happen:
> ...
> 
> > Shouldn't both TIME and MIN cases be uniform in returning -1/EAGAIN
> > on non-blocking descriptors?
> 
> It means that libc_r MIN/TIME handling should be fixed to conform POSIX
> and not general MIN/TIME handling way.

Not exactly, I'm afraid.  If the system returns 0 from read(), libc_r
has nothing else to do but to pass this 0 to the application because
it may be the EOF sign.  Of course, the issue is more complex then I
outlined, as Bruce Evans has pointed out.  However, why to treat TIME
differently from MIN in the system?

-- 
Yar