From owner-freebsd-arch@FreeBSD.ORG Wed Apr 9 08:14:46 2003 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4096537B401; Wed, 9 Apr 2003 08:14:46 -0700 (PDT) Received: from mail.pcnet.com (mail.pcnet.com [204.213.232.4]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7C7AB43FA3; Wed, 9 Apr 2003 08:14:45 -0700 (PDT) (envelope-from eischen@pcnet1.pcnet.com) Received: from pcnet1.pcnet.com (localhost [127.0.0.1]) by mail.pcnet.com (8.12.8/8.12.1) with ESMTP id h39FEiBg010169; Wed, 9 Apr 2003 11:14:44 -0400 (EDT) Received: from localhost (eischen@localhost)h39FEhvp010166; Wed, 9 Apr 2003 11:14:43 -0400 (EDT) Date: Wed, 9 Apr 2003 11:14:43 -0400 (EDT) From: Daniel Eischen To: Yar Tikhiy In-Reply-To: <20030409113653.GA63770@comp.chem.msu.su> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: "Andrey A. Chernov" cc: arch@freebsd.org Subject: Re: termios & non-blocking I/O X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Apr 2003 15:14:46 -0000 On Wed, 9 Apr 2003, Yar Tikhiy wrote: > 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? As Bruce pointed out, libc_r correctly doesn't go near TIME/MIN handling. This is a known problem when using libc_r and has been raised in the past. It's just too messy for libc_r to try and deal with this. It shouldn't be a problem with the threadsNG. -- Dan Eischen