From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21223 invoked by alias); 20 Jul 2011 15:12:52 -0000 Received: (qmail 21214 invoked by uid 22791); 20 Jul 2011 15:12:51 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mail.codesourcery.com (HELO mail.codesourcery.com) (38.113.113.100) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 20 Jul 2011 15:12:26 +0000 Received: (qmail 21799 invoked from network); 20 Jul 2011 15:12:26 -0000 Received: from unknown (HELO scottsdale.localnet) (pedro@127.0.0.2) by mail.codesourcery.com with ESMTPA; 20 Jul 2011 15:12:26 -0000 From: Pedro Alves To: pmuldoon@redhat.com Subject: Re: [rfc] Prompt memory management/cleanups Date: Wed, 20 Jul 2011 15:15:00 -0000 User-Agent: KMail/1.13.6 (Linux/2.6.38-8-generic; KDE/4.6.2; x86_64; ; ) Cc: gdb-patches@sourceware.org References: <201107201543.12940.pedro@codesourcery.com> In-Reply-To: MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201107201612.23708.pedro@codesourcery.com> X-IsSubscribed: yes Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2011-07/txt/msg00535.txt.bz2 On Wednesday 20 July 2011 16:04:16, Phil Muldoon wrote: > Pedro Alves writes: > > > On Wednesday 20 July 2011 15:30:19, Phil Muldoon wrote: > >> s = get_prompt (0) > >> set_prompt (s, 0) > >> > >> Without that check, 'PROMPT (level)' would be freed, but 's' points to > >> that. So you set garbage. get_prompt returns a pointer, not a copy. > > > > I'm probably missing something, but isn't it just > > a matter of instead of having: > > > > + xfree (PROMPT (level)); > > + PROMPT (level) = xstrdup (s); > > > > you have: > > > > + char *newp = xstrdup (s); > > + xfree (PROMPT (level)); > > + PROMPT (level) = newp; > > > > ? > > Yeah I noted we could do that in my reply. Sure we can do that, I'm not > opposed to it. But I am not sure on your objection to the check we make > first instead of the xstrdup? If PROMPT (level) == s, then there is no > need to copy the contents of s into PROMPT, it is already there? The > user is effectively asking for a noop? You've asked for comments on the API, and IMO this makes for a weird API, because the caller of set_prompt needs to know whether set_prompt will take ownership of the pointer or not depending on where the pointer came from. I haven't looked at the callers -- that's why I asked what would need to change. :-) -- Pedro Alves