220 31797 <3421677.yAxhhm3ryH@tjmaciei-mobl1> article Path: news.gmane.org!.POSTED!not-for-mail From: Thiago Macieira Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: This variable should not be named: an identifier (not) to remember Date: Tue, 28 Mar 2017 00:04:11 -0700 Lines: 52 Approved: news@gmane.org Message-ID: <3421677.yAxhhm3ryH@tjmaciei-mobl1> References: <985b9b2a-c734-45eb-95f4-db4dc0d309a1@isocpp.org> <6096248.pKJ4QPQkKS@tjmaciei-mobl1> <4E0805FE-B97D-4A93-956D-9281B3207F39@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1490684658 3248 195.159.176.226 (28 Mar 2017 07:04:18 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 28 Mar 2017 07:04:18 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBCB4TK757YBRB34V5DDAKGQEDDWT5NI@isocpp.org Tue Mar 28 09:04:13 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wr0-f198.google.com ([209.85.128.198]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cslAo-00005N-3I for gclcip-std-proposals@m.gmane.org; Tue, 28 Mar 2017 09:04:10 +0200 Original-Received: by mail-wr0-f198.google.com with SMTP id 58sf47317381wrv.23 for ; Tue, 28 Mar 2017 00:04:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding: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=wUAb9/giW+KU4FhLSEXY7GjLvrDDzYj1lJ2w6BQevvQ=; b=xyz8yEz/CkEkJQrfBZvN160kEA/EUxWeRruemqkbIYebJ+xf+r4FhQBwev+/pt9A4Y SL+47/pezxtQd9A2N9zx3xQKyJ+ca9lPGDsJJDLhdmNl2hULA/FNGwCCJW4en+KB2jKZ kTy60G9qmSI4KX1LqglJIQ61E0BGWuQsJvVvOFxHnhUe4JoChfNZOK7D/oBK+UT6MzJN IMM8dBga6utx2U/BMYQXz2vbb0haYtAcLB2zPe9HFpuTKXaIYNdzo/LDTXOhDJNIL7uR 149N8mAvKQ7HW2skyxQuVMiy818p0/DiydQk1wSrFCiagEvKTHis+syyahZTn0tZTkH6 4Dyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding: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=wUAb9/giW+KU4FhLSEXY7GjLvrDDzYj1lJ2w6BQevvQ=; b=bLWjALYTqlb/mjZuhS/dQKnmyq8lBUzcwS5PLwt0u84bUxhItg2PvcAK4ktlqF1sZP BwAxhuqCmw/cY9ccKdfrWu2/poJ0hYWR0pJaP04hhKBHPP05z5FOzdDDSGX0I9ndwvNh iaROkvqm/nhX7AMSIjXD8+P37WhBez7BIO9pqCidleyQBAH3avgH5flmNJFFwiKctGP+ 8tfQ2V89YXS/gXsRHjOwW14v9TdHhvg7brTmJ4/XVTfWSmqC91v67mnGQU0+LkT6Ke/l lGFTp44TnlllMCjo2LcrMH16Pt+atiDA+LnC7aZ7dOQj48ssC1qqeb+Qhufb2kXmtTwF I8Y X-Gm-Message-State: AFeK/H3URQZIZBW0rhbyNKTRCc8r7qB/iaAoeY5wiGC6ziHNtJdfULc4pLyEeEGRUXBe7Q== X-Received: by 10.223.163.206 with SMTP id m14mr1675122wrb.15.1490684656226; Tue, 28 Mar 2017 00:04:16 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.25.160.139 with SMTP id j133ls893094lfe.48.gmail; Tue, 28 Mar 2017 00:04:14 -0700 (PDT) X-Received: by 10.25.227.5 with SMTP id a5mr12939958lfh.118.1490684654724; Tue, 28 Mar 2017 00:04:14 -0700 (PDT) Original-Received: from gondolin.macieira.info (gondolin.macieira.info. [2a01:4f8:d13:f81:21c:14ff:fe01:12a3]) by mx.google.com with ESMTP id y25si1493089ljd.181.2017.03.28.00.04.14 for ; Tue, 28 Mar 2017 00:04:14 -0700 (PDT) Received-SPF: pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) client-ip=2a01:4f8:d13:f81:21c:14ff:fe01:12a3; Original-Received: from tjmaciei-mobl1.localnet (unknown [IPv6:2601:1c0:4501:5f9f:a40e:c587:f6be:c56d]) by gondolin.macieira.info (Postfix) with ESMTPSA id BA92211B7CE for ; Tue, 28 Mar 2017 00:04:13 -0700 (PDT) In-Reply-To: <4E0805FE-B97D-4A93-956D-9281B3207F39@gmail.com> X-Original-Sender: thiago@macieira.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of thiago@macieira.org designates 2a01:4f8:d13:f81:21c:14ff:fe01:12a3 as permitted sender) smtp.mailfrom=thiago@macieira.org 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:31797 Archived-At: Em segunda-feira, 27 de mar=C3=A7o de 2017, =C3=A0s 23:47:55 PDT, Alberto B= arbati=20 escreveu: > > And yet it's in use. > > https://github.com/v8/v8/blob/master/src/x64/codegen-x64.cc#L33 >=20 > Thanks Thiago for the pointer. According to my (possibly incorrect) > interpretation this code raises undefined behavior because __ is reserved > "for any use", which I would expect includes the use as a macro name. I m= ay > be wrong, but I'd expect little sympathy in the committee about potential= ly > breaking it. By the way, this code might possibly not break, because they > were clever to put #undefs in it. Incidentally, the code would indeed bre= ak > if we defined __ to be a macro... Right. We can say it's V8's own fault for using a reserved identifier. It's= =20 like when Qt (qlalr) had an identifier called _Nullable, but that got=20 repurposed by a recent Clang change. I'm just saying it's known to be in use in a fairly major project. You know= ,=20 the one that is behind Node.js and a whole ecosystem. The argument in the= =20 paper that says it's little used is incorrect: it's not like pre-C++11 "aut= o",=20 which had exactly one use in the entire Microsoft source code. I guess we could convince GCC and Clang to print a warning about it if it= =20 looks like this is going forward, so the V8 developers start fixing it. May= be=20 we'll get some of these fixed too: http://lxr.free-electrons.com/source/include/linux/compiler.h#L115 http://lxr.free-electrons.com/source/include/asm-generic/fixmap.h#L73 --=20 Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org Software Architect - Intel Open Source Technology Center --=20 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 e= mail 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/3421677.yAxhhm3ryH%40tjmaciei-mobl1. .