From owner-freebsd-hackers Tue Sep 16 01:31:25 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id BAA11076 for hackers-outgoing; Tue, 16 Sep 1997 01:31:25 -0700 (PDT) Received: from ocean.campus.luth.se (ocean.campus.luth.se [130.240.194.116]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id BAA11052; Tue, 16 Sep 1997 01:30:55 -0700 (PDT) Received: (from karpen@localhost) by ocean.campus.luth.se (8.8.5/8.8.5) id KAA04626; Tue, 16 Sep 1997 10:35:49 +0200 (CEST) From: Mikael Karpberg Message-Id: <199709160835.KAA04626@ocean.campus.luth.se> Subject: Re: What is wrong with this snipet? In-Reply-To: <199709160512.AAA00456@dyson.iquest.net> from "John S. Dyson" at "Sep 16, 97 00:12:43 am" To: dyson@FreeBSD.ORG Date: Tue, 16 Sep 1997 10:35:49 +0200 (CEST) Cc: freebsd-hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL31H (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk According to John S. Dyson: > Simon Shapiro said: > > > > Hi Jason Thorpe; On 14-Sep-97 you wrote: > > > On Sat, 13 Sep 1997 16:34:42 -0700 (PDT) > > > Simon Shapiro wrote: > > > > > > > Why would the following segfault on 6 of the 10 iterations? > > > > > > In the FreeBSD implementation of RFMEM (which does not match Plan 9's), > > > the child gets the same stack as the parent. If you "return" in the > > > child, > > > someone's stack gets munched. > > > > Not exactly useful, I'd say... > > > It actually is -- you just don't call RFMEM in the same way that you > would call vfork. It is doing good things at work. This is kinda interesting. You can't move forward or backwards in the stack, which means you can't call functions or return from functions. You can possibly calculate two values at the same time, withing the same function, without calling another function. This doesn't seem overly useful, however. What am I missing? Could you make a short example of a use for this? /Mikael