From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 106095 invoked by alias); 27 Jun 2018 23:37:37 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 106076 invoked by uid 89); 27 Jun 2018 23:37:37 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-25.0 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,GIT_PATCH_0,GIT_PATCH_1,GIT_PATCH_2,GIT_PATCH_3,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=facilities, highlight X-HELO: mail-oi0-f65.google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:cc:from:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=BDMYMvah807vgKrNuFYw+2ckhm6yTGQIqmlyoGiw/EM=; b=gD/6nhCnh2Mq3e0uo8ivZhpthYMl+Qk1OKCD8PYAhE6Y4UIG+hebFMTOMgT7gu9jY/ /qf+RjkqChA0i8OQacwmd1J2pP7Nvi0s1x7+1VVGjvkyo4Q4VHHxitpV8rEl4C+px4F2 7dGwiV3YnJhiGx5Tlxp+1bjuW1/gG09uA4hmnpGkv1T0PcOaO/Km+ojl2WzQ/wgIrWrI EGwHR9vQ803oDzqFyROyRR7yRUOiV6Za/iWZ8hwZmhmPvl5/bj7HWrB+5O4k5h7ygid3 t+SqOflbIM/TqsYOW3TmMbPwWU6LAv7FwF5O5YoyeVX0WA210oDPv9tjWg605GzN9bEn xPtQ== Return-Path: Subject: PING [PATCH] mention disabling GCC built-ins for customization To: Andreas Schwab References: <2f2f96d3-5487-f791-8554-310beae0721b@gmail.com> <51382872-07a8-91af-01b2-2511e2260e3b@gmail.com> Cc: GNU C Library From: Martin Sebor Message-ID: Date: Wed, 27 Jun 2018 23:37:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <51382872-07a8-91af-01b2-2511e2260e3b@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2018-06/txt/msg00868.txt.bz2 Ping: https://sourceware.org/ml/libc-alpha/2018-06/msg00428.html If there are no further comments I'd like to commit this change later this week. On 06/14/2018 01:11 PM, Martin Sebor wrote: > On 06/14/2018 01:25 AM, Andreas Schwab wrote: >> On Jun 13 2018, Martin Sebor wrote: >> >>> diff --git a/manual/stdio.texi b/manual/stdio.texi >>> index 38be236..d945955 100644 >>> --- a/manual/stdio.texi >>> +++ b/manual/stdio.texi >>> @@ -2963,7 +2963,11 @@ The facilities of this section are declared in >>> the header file >>> >>> @strong{Portability Note:} The ability to extend the syntax of >>> @code{printf} template strings is a GNU extension. ISO standard C has >>> -nothing similar. >>> +nothing similar. When using the GNU C compiler or any other compiler >>> +that interprets calls to standard I/O functions according to the rules >>> +of the language standard it is necessary to disable such handling by >>> +the appropriate compiler option. Otherwise the behavior of a program >>> +that relies on the extension is undefined. >> >> The manual already says that redefining existing conversions causes >> problems: >> >> You can redefine the standard output conversions, but this is >> probably >> not a good idea because of the potential for confusion. Library >> routines >> written by other people could break if you do this. >> >> We should extend that with a stronger language, independent of any >> compiler behaviour. > > That sounds fine to me. Attached is an updated patch that also > adds text to this paragraph. I added a Portability Note before > the text to highlight the portability impact, similarly to > the prior paragraph. > > Martin