Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756305AbXJISzV (ORCPT ); Tue, 9 Oct 2007 14:55:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751600AbXJISzH (ORCPT ); Tue, 9 Oct 2007 14:55:07 -0400 Received: from ip-svs-1.Informatik.Uni-Oldenburg.DE ([134.106.12.126]:46130 "EHLO schlidder.svs.informatik.uni-oldenburg.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750885AbXJISzG (ORCPT ); Tue, 9 Oct 2007 14:55:06 -0400 X-Greylist: delayed 1264 seconds by postgrey-1.27 at vger.kernel.org; Tue, 09 Oct 2007 14:55:06 EDT Date: Tue, 9 Oct 2007 20:33:59 +0200 From: Philipp Matthias Hahn To: "Ahmed S. Darwish" Cc: Kernel Mailing List Subject: Re: [PATCH] NTFS error messages: replace static char pointers by static char arrays Message-ID: <20071009183359.GB3945@titan.lahn.de> Mail-Followup-To: "Ahmed S. Darwish" , Kernel Mailing List References: <470AA75E.7010508@gmail.com> <20071009124035.GA4245@Ahmed> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20071009124035.GA4245@Ahmed> Organization: UUCP-Freunde Lahn e.V. User-Agent: Mutt/1.5.16 (2007-06-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1875 Lines: 52 Hello! On Tue, Oct 09, 2007 at 02:40:35PM +0200, Ahmed S. Darwish wrote: > On Tue, Oct 09, 2007 at 01:55:42AM +0400, Dmitri Vorobiev wrote: > > The patch below contains a small code clean-up for the NTFS driver: all > > static char pointers to error message strings have been replaced by > > static char arrays. char * a = "a"; // pointer and content can be changed const char * b = "b"; // the thing pointed to is const char * const c = "c"; // the pointer is const const char * const d = "d"; // pointer and content can't be changed void foo(void) { *a = 'A'; a++; *b = 'B'; // error: assignment of read-only location b++; *c = 'C'; c++; // error: increment of read-only variable 'c' *d = 'D'; // error: assignment of read-only location d++; // error: increment of read-only variable 'd' } > Isn't the only difference between char *c = "msg" and char c[] = "msg" is > that the first is a non-const pointer to a const char array while the second > is a modifiable char array ? $ cat [ab].c const char *a = "a"; const char b[] = "b"; $ gcc -c [ab].c $ size [ab].o text data bss dec hex filename 2 4 0 6 6 a.o 2 0 0 2 2 b.o 'a' has two entries: one for the named read-writeable pointer, and one for the anonymous read-only string, the pointer points to. 'b' has a single entry: just the named read-only string. BYtE Philipp -- / / (_)__ __ ____ __ Philipp Hahn / /__/ / _ \/ // /\ \/ / /____/_/_//_/\_,_/ /_/\_\ pmhahn@titan.lahn.de - 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/