Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756477AbZGFGX6 (ORCPT ); Mon, 6 Jul 2009 02:23:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752903AbZGFGXu (ORCPT ); Mon, 6 Jul 2009 02:23:50 -0400 Received: from mail-qy0-f193.google.com ([209.85.221.193]:34268 "EHLO mail-qy0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752778AbZGFGXu convert rfc822-to-8bit (ORCPT ); Mon, 6 Jul 2009 02:23:50 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=YJlttq4xsXpFPskjQVTVdSZu2FrPVVcervB9mR3UKhT4HA0OTYoDsLQYDN5ovRPr7J Y5RvfSLFWzR+cyh1JLwsRs7/ybM24yT6bgnAqaRS1lpTRRY/sE0VPf5httFJAQbwlCaf 1g0t/JgPyU/Pq5ZTKn+u4N8UjlAIjQS2H2suI= MIME-Version: 1.0 In-Reply-To: <4A51966C.3000102@free.fr> References: <20090703015554.GB5880@cr0.nay.redhat.com> <20090703071504.GG5880@cr0.nay.redhat.com> <412e6f7f0907030040v6133badat7058186a01d78f44@mail.gmail.com> <20090703081655.GH5880@cr0.nay.redhat.com> <412e6f7f0907030127u3d6806dfo9168600e7c71b241@mail.gmail.com> <20090703094229.GI5880@cr0.nay.redhat.com> <412e6f7f0907030259m5556ee2fobbb58d377bce4d17@mail.gmail.com> <4A4DDD54.9030206@free.fr> <412e6f7f0907051812q4b3d7bcfkff73c75da14a9cf4@mail.gmail.com> <4A51966C.3000102@free.fr> Date: Mon, 6 Jul 2009 14:23:53 +0800 Message-ID: <412e6f7f0907052323g114ccbe0n2d17f3d870e42470@mail.gmail.com> Subject: Re: PROPOSAL: extend pipe() to support NULL argument. From: Changli Gao To: Albert ARIBAUD Cc: Linux Kernel Mailing List , Amerigo Wang , Linus Torvalds Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 981 Lines: 28 On Mon, Jul 6, 2009 at 2:15 PM, Albert ARIBAUD wrote: >> >> >> pipe doesn't support llseek. > > I wasn't thinking of actively seeking a file position, but simply that reads > and writes were independent (and both variable) in size, thus even without > (l)seeking, each endpoint has an independent read (resp. write) position to > track what's been read from (resp.written into) it at any time, and such a > position is, IIUC, single for a given fd, making a fd (a struct file) > insufficient for representing a pipe. > > Amicalement, > -- > Albert. > pipe doesn't refer to pos when reading or writing. Please refer to pipe_read() and pipe_write() for more detail. -- Regards， Changli Gao(xiaosuo@gmail.com) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/