From owner-cvs-all Thu Dec 13 10: 8:44 2001 Delivered-To: cvs-all@freebsd.org Received: from elvis.mu.org (elvis.mu.org [216.33.66.196]) by hub.freebsd.org (Postfix) with ESMTP id 05A4237B405; Thu, 13 Dec 2001 10:08:36 -0800 (PST) Received: by elvis.mu.org (Postfix, from userid 1192) id 7784381E0B; Thu, 13 Dec 2001 12:08:30 -0600 (CST) Date: Thu, 13 Dec 2001 12:08:30 -0600 From: Alfred Perlstein To: Bruce Evans Cc: cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/fifofs fifo_vnops.c Message-ID: <20011213120830.E79896@elvis.mu.org> References: <20011212125324.R92148@elvis.mu.org> <20011213224148.M469-100000@gamplex.bde.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011213224148.M469-100000@gamplex.bde.org>; from bde@zeta.org.au on Thu, Dec 13, 2001 at 10:57:16PM +1100 Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * Bruce Evans [011213 05:56] wrote: > On Wed, 12 Dec 2001, Alfred Perlstein wrote: > > > * Bruce Evans [011212 06:13] wrote: > > > On Wed, 12 Dec 2001, Alfred Perlstein wrote: > > > > > > > alfred 2001/12/12 01:35:33 PST > > > > > > > > Modified files: > > > > sys/fs/fifofs fifo_vnops.c > > > > Log: > > > > Fix select on named pipes without a reader. > ^^^^^^ ITYM "writer" > > > > > > > > PR: kern/19871 > > > > MFC after: 1 month > > > > > > No, it will be backed out. I believe other systems implement this by > > > making the semantics of select() incompatible with read(). They don't > > > just break read(). > > > > Could you be more clear on how this breaks read(2)? > > >From POSIX.1-200x-draft7 (this has not changed since at least the 1990 > version): > > ! 36609 When attempting to read from an empty pipe or FIFO: > ! > ! 36610 * If no process has the pipe open for writing, read( ) shall return 0 to indicate end-of-file. > > The changes make read() block instead, at least for the non-O_NONBLOCK case. > I'm not sure of the effect of the change in the O_NONBLOCK case, but it > seems likely that -1/EAGAIN is returned instead of 0/no-error. Ok, I can fix this. (I hope :) ) -- -Alfred Perlstein [alfred@freebsd.org] 'Instead of asking why a piece of software is using "1970s technology," start asking why software is ignoring 30 years of accumulated wisdom.' http://www.morons.org/rants/gpl-harmful.php3 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message