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Date: Thu, 12 Mar 2020 04:05:56 -0400 (EDT)
From: Thomas Dickey <dickey AT his DOT com>
To: =?utf-8?B?w4VrZQ==?= Rehnman <ake DOT rehnman AT gmail DOT com>
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Subject: Re: Setting termios VMIN > 0 and VTIME > 0 on non blocking file
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----- Original Message -----
| From: "Åke Rehnman" <ake DOT rehnman AT gmail DOT com>
| To: "cygwin" <cygwin AT cygwin DOT com>
| Sent: Wednesday, March 11, 2020 4:48:05 PM
| Subject: Setting termios VMIN > 0 and VTIME > 0 on non blocking file

| Hello all,
| 
| opening a file (serial port) with O_NONBLOCK and subsequently setting
| termios VMIN and VTIME > 0 makes read() never ever return any data
| (returns EAGAIN indefinitely).
| 
| Don't ask my why one would want to do something like this but apparently
| the "screen" program think this is a good way of doing things...
| 
| Nevertheless not returning any data ever seems wrong.
| 
| Any insight on how it is supposed to work is welcome.

If not "correct", it's certainly inconsistent with all other systems.
I noticed it recently:

https://invisible-island.net/ncurses/tack/CHANGES.html#t20200220

https://github.com/cygwinports/tack/issues/1

It's either recently-broken, or just coincidence :-)

-- 
Thomas E. Dickey <dickey AT invisible-island DOT net>
http://invisible-island.net
ftp://ftp.invisible-island.net
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