From owner-freebsd-chat Sun Jan 7 20:32:55 1996 Return-Path: owner-chat Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id UAA10949 for chat-outgoing; Sun, 7 Jan 1996 20:32:55 -0800 (PST) Received: from bacchus.eng.umd.edu (bacchus.eng.umd.edu [129.2.94.5]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id UAA10858 for ; Sun, 7 Jan 1996 20:32:08 -0800 (PST) Received: from cappuccino.eng.umd.edu (cappuccino.eng.umd.edu [129.2.98.14]) by bacchus.eng.umd.edu (8.7.3/8.7) with ESMTP id XAA09201 for ; Sun, 7 Jan 1996 23:31:35 -0500 (EST) Received: (chuckr@localhost) by cappuccino.eng.umd.edu (8.7.3/8.6.4) id XAA08115; Sun, 7 Jan 1996 23:31:31 -0500 (EST) Date: Sun, 7 Jan 1996 23:31:27 -0500 (EST) From: Chuck Robey X-Sender: chuckr@cappuccino.eng.umd.edu To: FreeBSD-chat@FreeBSD.org Subject: cpp construction Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-chat@FreeBSD.org Precedence: bulk There's a construction that's used (I think) to supply prototypes that I've never really understood, and I was wondering if anyone might be feeling like a short lecture here. The example is from /usr/src/sys/miscfs/nullfs/null_subr.c, which I happen to be studying right now, but I've seen this construction a lot of times before (but with no more comprehension). Anyways, here's the example: static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp, struct vnode **vpp)); It's that __P thing, with the double parens, that has me wondering. I'd really appreciate some help. I didn't put this in questions because it's so wildly different from the kind of stuff normally seen there, and I didn't put it in hackers because it has nothing to do with anything going on, it's just me studying the system. If someone wants to transplant this to another list, fine with me, but it seemed a good compromise here in -chat. ============================================================================ Chuck Robey chuckr@eng.umd.edu -- I run FreeBSD on n3lxx and Journey2 --------------------------------------------------------------------------- The Dilbert Zone is Dilbert's new WWW home! The area features never-before-seen original sketches of Dilbert, a photo tour of Scott Adams' studio, Dilbert Trivia and memorabilia, high school photos and much more!: