220 19299 article Path: news.gmane.org!not-for-mail From: Jim Porter Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Testing for supported features: Per-feature macros? Sentinel compilation? Date: Sun, 26 Jul 2015 23:02:57 -0500 Lines: 34 Approved: news@gmane.org Message-ID: References: <1720943.XpK8Tt98Hf@tjmaciei-mobl4> <4897684.zJq850IzGK@tjmaciei-mobl4> <2a1df8fc-7d85-4c27-a8c7-102791d2fcf6@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed X-Trace: ger.gmane.org 1437969804 16194 80.91.229.3 (27 Jul 2015 04:03:24 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 27 Jul 2015 04:03:24 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDYZZG6PQYFRBAG322WQKGQEW7IPEGY@isocpp.org Mon Jul 27 06:03:16 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-la0-f70.google.com ([209.85.215.70]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZJZdC-000591-PK for gclcip-std-proposals@m.gmane.org; Mon, 27 Jul 2015 06:03:14 +0200 Original-Received: by lafd3 with SMTP id d3sf23285927laf.1 for ; Sun, 26 Jul 2015 21:03:13 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:to:from:subject:date:lines:message-id:references :mime-version:content-type:user-agent:in-reply-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=ECUMR1+I7NB/Bq99z2Pyej061SLFvSKt4jB7wECypqE=; b=fx95nsnogHtggxyHAACesD5VoNk7wKXUgmfcZ1cuQsGzQmOjhz50F3oAF4zN3HRclo /yCNRsxlYHgqTr50DcA4tfKWzg4o1IySQSVwrmufCxLp2UMJfcK7iSHaOwTCgSTKVxn7 mDd3km0UO2ZGGmAVmwcWZKXw66K35G6kd+EQw3EmIG52fcL8J9I6v5nOSstUTlGTpEgk t6EBYyx/cdb6pLlIT3HgfPPHQDdVZXFEKh+7EbKNBCwd24QET4wfc6/IhO45dc9+lOrw t/0nPHlqDBl/KLYvFXkBgfBQGZYo1uN/Lv27eZVKxt3fjKlShqWsR9eUTRe0BmvyAe9V X-Gm-Message-State: ALoCoQkD6QLf/fdLx8lTEo+X8yfHp884XLXlOd51ykvgUtVuEqdWwSMhg/GfAbh39cC7nX/lK2WB X-Received: by 10.152.87.46 with SMTP id u14mr8712844laz.5.1437969793617; Sun, 26 Jul 2015 21:03:13 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.152.10.74 with SMTP id g10ls608672lab.92.gmail; Sun, 26 Jul 2015 21:03:11 -0700 (PDT) X-Received: by 10.112.61.132 with SMTP id p4mr25023202lbr.48.1437969791880; Sun, 26 Jul 2015 21:03:11 -0700 (PDT) Original-Received: from plane.gmane.org (plane.gmane.org. [80.91.229.3]) by mx.google.com with ESMTPS id jv10si14274560lbc.13.2015.07.26.21.03.11 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Sun, 26 Jul 2015 21:03:11 -0700 (PDT) Received-SPF: pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) client-ip=80.91.229.3; Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1ZJZd6-00053x-9F for std-proposals@isocpp.org; Mon, 27 Jul 2015 06:03:08 +0200 Original-Received: from 71-87-112-150.dhcp.mdsn.wi.charter.com ([71.87.112.150]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 27 Jul 2015 06:03:08 +0200 Original-Received: from jvp4846 by 71-87-112-150.dhcp.mdsn.wi.charter.com with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 27 Jul 2015 06:03:08 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 25 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: 71-87-112-150.dhcp.mdsn.wi.charter.com User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 In-Reply-To: <2a1df8fc-7d85-4c27-a8c7-102791d2fcf6@isocpp.org> X-Original-Sender: jvp4846@g.rit.edu X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of gclcip-std-proposals@m.gmane.org designates 80.91.229.3 as permitted sender) smtp.mail=gclcip-std-proposals@m.gmane.org Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:19299 Archived-At: On 7/26/2015 9:36 PM, denis bider wrote: > It is not, in fact, readily accessible now. It is an inferior solution > that has not yet been implemented by any compiler that I have access to. Nor is your proposal; any new C++ feature of this sort would be unusable if you need to compile on sufficiently-old compilers. > > > Sentinel compilation would imply a major feature to the language. > > > You can already do that with a configure script, if you want, though. > > > > That opens a whole other can of worms, which sentinel compilation would > > make it easy to avoid. Perhaps I'm just misunderstanding what you mean, but I'm not sure how a build system that understands the tools it's using to build your software is a "can of worms". Cross-platform build configuration already has a long history of use in general-purpose build systems (autotools, CMake, and many others support it). While you might not like autotools or CMake, I'm sure you could find a build system that you don't mind that lets you perform configuration-time compilation tests. This gives you all the flexibility of your proposal (albeit with different syntax) with the added benefit that you can even support C++98 compilers. - Jim -- --- 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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/. .