220 29108 article Path: news.gmane.org!.POSTED!not-for-mail From: "'Matt Calabrese' via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Removing trivial undefined behaviour Date: Wed, 26 Oct 2016 11:44:58 -0400 Lines: 126 Approved: news@gmane.org Message-ID: References: <35daf87a-bf1d-46de-b16c-c2965fbadc8f@isocpp.org> <9e242562-aba1-4f8d-8e0a-b2de34f6a10b@isocpp.org> <1314a997-2f74-4b52-9755-bc9d1deb6982@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary=001a1143f082e0e3bc053fc681c1 X-Trace: blaine.gmane.org 1477496712 9750 195.159.176.226 (26 Oct 2016 15:45:12 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 26 Oct 2016 15:45:12 +0000 (UTC) To: "ISO C++ Standard - Future Proposals" Original-X-From: std-proposals+bncBCGNLO5F34OBB646YPAAKGQE2BF2BSY@isocpp.org Wed Oct 26 17:45:04 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f200.google.com ([209.85.161.200]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bzQNt-0000jn-Jt for gclcip-std-proposals@m.gmane.org; Wed, 26 Oct 2016 17:44:57 +0200 Original-Received: by mail-yw0-f200.google.com with SMTP id h139sf12317564ywc.9 for ; Wed, 26 Oct 2016 08:45:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :x-original-sender:x-original-authentication-results:reply-to :precedence:mailing-list:list-id:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=zhWFOmN7XwoYLAjHnLS3cl3HQbapF4k5SPRdSp21rwo=; b=I0sMDiY1m00BpsFGFgCllRJmYsNQJVseTmlJp8o+3DNQiDCej+49BIbRfMTjo19f2+ +fNjYPNovF3fK/+Sh1L1VAdwxhXB/NfY1mGPo+9jSfQUpLZXkXyZ3K34PJnwnK2+oQgE mGDeNGFVQqF0HDUrW+9CJsUY9nXm4gtiW4dS2IiAcaEEzBrK93AE0TRElzBZdu59PbkQ tlbG45ktigf1IhPe2bGNTu9qrCqinqpWgMHj1IbX6iG7bTg6ZgdUmW5GDrX3pcFcHQ4R wvTgTbcGPGsHizw4Wj9pujUTDVjC5GApBSJnYaYcmiTenw77t5vR2iJa8IuaUxlxdhBr 3rNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=zhWFOmN7XwoYLAjHnLS3cl3HQbapF4k5SPRdSp21rwo=; b=mHOS1vYGICKaOZ630nq2+H3GfYbLudXC4NtbaFW4Y2+3vyVrgdB17oXFqRXPZeNXtD dk5l9EfNolrvHgsisQDR0xBjVIzx3RuHBoBKz3Bi7ynVoXNxV34Q6Jcj3EdwNTG6i7VN MHp+A0WowIX2Z5ELa2r951kdqZ5uE5f5JcZWNeEHRaXFeb1dxrQu51elma38Tn3QKyYa Tri+p46QRv+v4nllL9Y0EMI/BN05FuMUD2C5cyEBI8//D6sLmcrqmubdYpfRrzLSp6Nx VjZUOO/+eaYHfi3Z+HaCUL9EVEXOBv+H0gWmJ2FzNZiXG7t3+f30JsOp19T+ZRC7VaR2 mEcg== X-Gm-Message-State: ABUngvdT9MjPpvsc1dQ/bluH/0SKBOqxmliNL1o0HtD/pRO5HCJkVFmnyYTd/uAUclYXzQ== X-Received: by 10.129.160.135 with SMTP id x129mr968637ywg.30.1477496699800; Wed, 26 Oct 2016 08:44:59 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.157.14.129 with SMTP id 1ls1772657otj.31.gmail; Wed, 26 Oct 2016 08:44:59 -0700 (PDT) X-Received: by 10.31.99.197 with SMTP id x188mr1646057vkb.125.1477496699068; Wed, 26 Oct 2016 08:44:59 -0700 (PDT) Original-Received: from mail-vk0-x233.google.com (mail-vk0-x233.google.com. [2607:f8b0:400c:c05::233]) by mx.google.com with ESMTPS id i187si1006087vkd.94.2016.10.26.08.44.59 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Oct 2016 08:44:59 -0700 (PDT) Received-SPF: pass (google.com: domain of calabrese@google.com designates 2607:f8b0:400c:c05::233 as permitted sender) client-ip=2607:f8b0:400c:c05::233; Original-Received: by mail-vk0-x233.google.com with SMTP id 14so4791921vke.5 for ; Wed, 26 Oct 2016 08:44:59 -0700 (PDT) X-Received: by 10.31.178.198 with SMTP id b189mr1668640vkf.70.1477496698604; Wed, 26 Oct 2016 08:44:58 -0700 (PDT) Original-Received: by 10.103.120.149 with HTTP; Wed, 26 Oct 2016 08:44:58 -0700 (PDT) In-Reply-To: <1314a997-2f74-4b52-9755-bc9d1deb6982@isocpp.org> X-Original-Sender: calabrese@google.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@google.com; spf=pass (google.com: domain of calabrese@google.com designates 2607:f8b0:400c:c05::233 as permitted sender) smtp.mailfrom=calabrese@google.com; dmarc=pass (p=REJECT dis=NONE) header.from=google.com X-Original-From: Matt Calabrese Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:29108 Archived-At: --001a1143f082e0e3bc053fc681c1 Content-Type: text/plain; charset=UTF-8 On Wed, Oct 26, 2016 at 11:34 AM, T. C. wrote: > > > On Wednesday, October 26, 2016 at 9:19:15 AM UTC-4, Tony V E wrote: >> >> >> >> On Wed, Oct 26, 2016 at 4:28 AM, T. C. wrote: >> >>> >>> >>> On Wednesday, October 26, 2016 at 3:20:55 AM UTC-4, Hans Guijt wrote: >>>> >>>> >>>> On Wednesday, October 26, 2016 at 9:11:26 AM UTC+2, T. C. wrote: >>>>> >>>>> >>>>> Because they are meant to be used as isdigit((unsigned char) c). >>>>> >>>> >>>> Great, in that case I'm sure there is no opposition to changing the >>>> signature to reflect this requirement? It's a much cleaner solution than >>>> requiring a cast in every invocation, after all. >>>> >>>> >>>> >>> The reason they take int is because they also accept EOF. That's C's >>> style, for better or worse. >>> >>> In any event, there's no way in hell C++ is going to change this. It's a >>> massive C compatibility break. >>> >> >> We could maybe overload the function: >> >> int isdigit(int c); >> bool isdigit(char c); >> >> No idea if that is a good idea. >> >>> >>> -- >> Be seeing you, >> Tony >> > > That breaks anything that expects ::isdigit to be unambiguous (e.g., pass > it to an algorithm). > I thought the standard doesn't sanction such uses of standard library facilities, unless I'm mistaken. -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/CANh8DEmWMr0u%3D%3DFPgaw4mnpv1UHCMnPfvonhJpwjTxuxw%2BLa%3Dg%40mail.gmail.com. --001a1143f082e0e3bc053fc681c1 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


On Wed, Oct 26, 2016 at 11:34 AM, T. C. <rs2740@gmail.com> wrote:


On We= dnesday, October 26, 2016 at 9:19:15 AM UTC-4, Tony V E wrote:

On Wed, Oct 26, 2016 at 4:28 AM, T. C. <rs2...@gmail.com> wrote:


On Wednesday= , October 26, 2016 at 3:20:55 AM UTC-4, Hans Guijt wrote:

On Wednesday, October 26, 2016 = at 9:11:26 AM UTC+2, T. C. wrote:

Because they are meant to be used as isd= igit((unsigned char) c).
=C2=A0
Grea= t, in that case I'm sure there is no opposition to changing the signatu= re to reflect this requirement? It's a much cleaner solution than requi= ring a cast in every invocation, after all.



The reason they take int is because they al= so accept EOF. That's C's style, for better or worse.
In any event, there's no way in hell C++ is going to change= this. It's a massive C compatibility break.

We could maybe overload the function:

i= nt isdigit(int c);
bool isdigit(char c);

No= idea if that is a good idea.


--
Be s= eeing you,
Tony

<= /div>
That breaks anything that expects ::isdigit=C2=A0to be una= mbiguous (e.g., pass it to an algorithm).=C2=A0

I thought the standard doesn't sanction such uses of s= tandard library facilities, unless I'm mistaken.=C2=A0

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