220 41224 <08290107-c63b-3ef6-09d4-16c7b6c495ab@honermann.net> article Path: news.gmane.org!.POSTED!not-for-mail From: Tom Honermann Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Modules and preambule, just why? Date: Wed, 5 Dec 2018 16:43:44 -0500 Lines: 35 Approved: news@gmane.org Message-ID: <08290107-c63b-3ef6-09d4-16c7b6c495ab@honermann.net> References: <16989401-2f0d-4200-997e-0ac60b47bec3@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed X-Trace: blaine.gmane.org 1544046101 15945 195.159.176.226 (5 Dec 2018 21:41:41 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 5 Dec 2018 21:41:41 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 To: std-proposals@isocpp.org, Ville Voutilainen Original-X-From: std-proposals+bncBDBNXSHG6UDBBEMNUHQAKGQEANAZSKA@isocpp.org Wed Dec 05 22:41:36 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io1-f71.google.com ([209.85.166.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gUevI-00043n-76 for gclcip-std-proposals@m.gmane.org; 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[184.106.54.99]) by mx.google.com with ESMTPS id r205si8573299itd.33.2018.12.05.13.43.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 Dec 2018 13:43:45 -0800 (PST) Received-SPF: pass (google.com: domain of tom@honermann.net designates 184.106.54.99 as permitted sender) client-ip=184.106.54.99; Original-Received: from smtp21.relay.ord1d.emailsrvr.com (localhost [127.0.0.1]) by smtp21.relay.ord1d.emailsrvr.com (SMTP Server) with ESMTP id CF2E4603D1; Wed, 5 Dec 2018 16:43:44 -0500 (EST) X-Auth-ID: tom@honermann.net Original-Received: by smtp21.relay.ord1d.emailsrvr.com (Authenticated sender: tom-AT-honermann.net) with ESMTPSA id 8CA046027C; Wed, 5 Dec 2018 16:43:44 -0500 (EST) X-Sender-Id: tom@honermann.net Original-Received: from [192.168.1.19] (pool-71-176-235-158.rcmdva.fios.verizon.net [71.176.235.158]) (using TLSv1.2 with cipher AES128-SHA) by 0.0.0.0:25 (trex/5.7.12); Wed, 05 Dec 2018 16:43:44 -0500 In-Reply-To: Content-Language: en-US X-Original-Sender: tom@honermann.net X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@honermann.net header.s=20180930-2j89z3ji header.b=kDMKUHnU; spf=pass (google.com: domain of tom@honermann.net designates 184.106.54.99 as permitted sender) smtp.mailfrom=tom@honermann.net; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=honermann.net 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:41224 Archived-At: On 12/5/18 2:01 PM, Ville Voutilainen wrote: > On Wed, 5 Dec 2018 at 20:47, wrote: >> After reading your answer and thinking about it in the last days, I thing I understand things a bit better now. >> First I understand that module are far less related to the linking problem than I first tough. >> Also, I think I better understand how they will actually work in real world application. >> >> Still, one question remains for me: >> If for example you wanna ship a library. >> As of today, you generally with the library the headers so that people using the library will be able to compile their code and make use of the library you made. >> But how does it work if you wanna use modules? do you ship a module file together with the lib? And if so, how do you intend to generate this module file? > Yes, you ship the module interface with your lib. You compile the > module for the target implementation you want to support. To be clear, I believe Ville means that you ship the module interface unit source code (not a binary module artifact as they are not portable) and you link any object files produced by compiling the module interface unit in your compiled library for your supported platforms. Tom. > >> Also note that even if I better understand the proposal now, my doubts about it and the need of declaring the module explicitly remains. >> In fact, I would have prefer an approach where the exported symbols are deduced from the code instead of having to declare it explicitly. > Deduced how? The problem we have today with headers is that everything > in a header needs to be parsed, whether part of the actual > interface of the library or not. Modules give us control over what > things are part of the interface and what things are not. > -- 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/08290107-c63b-3ef6-09d4-16c7b6c495ab%40honermann.net. .