From: Julio Guerra <julio@farjump.io>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [BUG] drivers/tty: read() on a noncanonical blocking tty randomly fails when VMIN > received >= buf
Date: Thu, 5 May 2016 01:27:28 +0200 [thread overview]
Message-ID: <3319f492-9b1b-d006-e903-7de761a87a53@farjump.io> (raw)
In-Reply-To: <572A80C0.4080704@hurleysoftware.com>
>> When a tty (here a slave pty) is set in noncanonical input and blocking read modes, a read() randomly blocks when:
>> "VMIN > kernel received >= user buffer size > 0".
>>
>> The standard says that read() should block until VMIN bytes are received [1][2]. Whether this is an implementation defined case not really specified by POSIX or not, it should not behave randomly (otherwise it really should be documented in termios manpage).
>
> This is not a bug.
>
> From the termios(3) man page:
>
> * MIN > 0; TIME == 0: read(2) blocks until the lesser of MIN bytes or the number of bytes requested are avail‐
> able, and returns the lesser of these two values.
>
This does not appear in my man...
Anyway, how do you explain the random behavior then?
--
Julio Guerra
next prev parent reply other threads:[~2016-05-04 23:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-04 23:00 Julio Guerra
2016-05-04 23:07 ` Peter Hurley
2016-05-04 23:27 ` Julio Guerra [this message]
2016-05-05 0:50 ` Peter Hurley
2016-05-05 10:08 ` One Thousand Gnomes
2016-05-05 15:28 ` Peter Hurley
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