From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10DE5C61CE8 for ; Sat, 19 Jan 2019 18:02:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DBE872084C for ; Sat, 19 Jan 2019 18:02:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728891AbfASSCB (ORCPT ); Sat, 19 Jan 2019 13:02:01 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:56552 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728643AbfASSCB (ORCPT ); Sat, 19 Jan 2019 13:02:01 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::bf5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id B19B114BC61D8; Sat, 19 Jan 2019 10:02:00 -0800 (PST) Date: Sat, 19 Jan 2019 10:02:00 -0800 (PST) Message-Id: <20190119.100200.853063369704641480.davem@davemloft.net> To: natechancellor@gmail.com Cc: isdn@linux-pingi.de, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ndesaulniers@google.com Subject: Re: [PATCH v2] isdn: avm: Fix string plus integer warning from Clang From: David Miller In-Reply-To: <20190110054107.6069-1-natechancellor@gmail.com> References: <20190108050649.9962-1-natechancellor@gmail.com> <20190110054107.6069-1-natechancellor@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 19 Jan 2019 10:02:00 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Nathan Chancellor Date: Wed, 9 Jan 2019 22:41:08 -0700 > A recent commit in Clang expanded the -Wstring-plus-int warning, showing > some odd behavior in this file. > > drivers/isdn/hardware/avm/b1.c:426:30: warning: adding 'int' to a string does not append to the string [-Wstring-plus-int] > cinfo->version[j] = "\0\0" + 1; > ~~~~~~~^~~ > drivers/isdn/hardware/avm/b1.c:426:30: note: use array indexing to silence this warning > cinfo->version[j] = "\0\0" + 1; > ^ > & [ ] > 1 warning generated. > > This is equivalent to just "\0". Nick pointed out that it is smarter to > use "" instead of "\0" because "" is used elsewhere in the kernel and > can be deduplicated at the linking stage. > > Link: https://github.com/ClangBuiltLinux/linux/issues/309 > Suggested-by: Nick Desaulniers > Signed-off-by: Nathan Chancellor > --- > > v1 -> v2: > > * Use "" instead of "\0", as they are equivalent, but "" can be > deduplicated by the linker, as pointed out by Nick. Applied, that was certainly a funny construct.... It obviously is trying to initialize the array elements to pointers to empty strings.