220 14874 <4720a9a6-24d5-4488-a229-2bdf2433fa03@isocpp.org> article Path: news.gmane.org!not-for-mail From: =?UTF-8?Q?Germ=C3=A1n_Diago?= Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Safer C++: never allow implicitly uninitialized variables? Date: Fri, 5 Dec 2014 22:10:24 -0800 (PST) Lines: 89 Approved: news@gmane.org Message-ID: <4720a9a6-24d5-4488-a229-2bdf2433fa03@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1799_1323316710.1417846224433" X-Trace: ger.gmane.org 1417846237 1124 80.91.229.3 (6 Dec 2014 06:10:37 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 6 Dec 2014 06:10:37 +0000 (UTC) To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDC2VXM4YYDRBUV3RKSAKGQEBHRU66Q@isocpp.org Sat Dec 06 07:10:31 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ob0-f198.google.com ([209.85.214.198]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Xx8ZY-0007C8-Cc for gclcip-std-proposals@m.gmane.org; Sat, 06 Dec 2014 07:10:28 +0100 Original-Received: by mail-ob0-f198.google.com with SMTP id vb8sf10439778obc.1 for ; Fri, 05 Dec 2014 22:10:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:subject:mime-version:content-type :x-original-sender:reply-to:precedence:mailing-list:list-id :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=9x1FkPzd8L7KKUSvhwV1HQvT7GHhwSnYhZg+icX0Y3w=; b=bR+tKja9Qayzx8tgyJD2epxPfJGK555RzNlJko+tWKelBuPazced7xuPSBRkU9OYde tjPWQcYDxgSuyeneXQCMIqmRrLRMMg4DT0OMZ6lvtUHAAX2Spy8M93S7X4h5zf6WCxX2 1MzWpDN4C71pfdGoHiTgeKJL9quoFncSIFFsM+K97rz1a3cRY2qcCjFJfky+dO4JeSMh Lh6g4aT+gjUHpZMdO1KXMcibBtO2OLr+2A78Bd0QJh8ARUe+ewQ0ZATMK5S+PxuYyQCE StXY/vW/KutXg+SW8XqjVACANr1tBGfOiX1f7f4r2+sRSPl91zrgOs6JTauSdrxA8+H2 10bg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:subject:mime-version :content-type:x-original-sender:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=9x1FkPzd8L7KKUSvhwV1HQvT7GHhwSnYhZg+icX0Y3w=; b=cuzjz58r+4jMDG7AY1IjDcIvMEO5HCAvGVImts6YWJ3dzlYg6DXO7FYAQZiMBPcDTG gzgXnO7kc6qLEGCAI5lyAuoVNnM7LGSuEKKep1id+rW9Hq6nUL+fnsZpz5mJ4ePrqNNT /tpiAQbMwHgiMJ6kXJqlZrpyJ6xGC96dVAI7orVqZrZLzZCe6uPy9YIzhA195zCKrZpl 80nq93FPgvS2A71Zb3fdBy02syTkLo/cRwTVF6DEd+zHmkVXRcLH/5amqD33AC4zowO1 PbbvNQmbeJyO3LJ9oRqm2K45uW4pVPzfIFKov/u42QnyBjWrT47PNsF2W5dkBG8G4Ug7 xclg== X-Gm-Message-State: ALoCoQmH/Y7eqXdYC5FqH3OWsP8JB1ovTUdUnfC54yriwUlpnmT3mh0is7bzg37leZN1omMmRnM9 X-Received: by 10.50.88.10 with SMTP id bc10mr6261056igb.5.1417846227271; Fri, 05 Dec 2014 22:10:27 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.11.42 with SMTP id v42ls1530991ioi.108.gmail; Fri, 05 Dec 2014 22:10:25 -0800 (PST) X-Received: by 10.50.110.42 with SMTP id hx10mr106369igb.16.1417846225938; Fri, 05 Dec 2014 22:10:25 -0800 (PST) X-Original-Sender: germandiago@gmail.com 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:14874 Archived-At: ------=_Part_1799_1323316710.1417846224433 Content-Type: multipart/alternative; boundary="----=_Part_1800_1643296638.1417846224433" ------=_Part_1800_1643296638.1417846224433 Content-Type: text/plain; charset=UTF-8 Hello everyone, I wonder if it would make sense to make variables in C++ automatically value-initialized or there would be problems. Since we are making c++ safer and safer, would it make sense to do the following? int a; //value-initialized to 0 Later, some syntax like in D language could be provided: int a = void; The rationale behind this change would be: - an uninitialized variable that is replaced by these new semantics does not produce incorrect behaviour. - makes the language safer to use. In the case where performance must be preserved, a compiler option with the old semantics would be enough. Would this make any sense or I am missing manu points? It looks to me that this could be backwards-compatible and the noly thing that could happen is a performance bug, which can be solved replacing iniitialization or by a compiler switch for large codebases. -- --- 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/. ------=_Part_1800_1643296638.1417846224433 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Hello everyone,

I wonder if it would ma= ke sense to make variables in C++ automatically value-initialized or there = would be problems.

Since we are making c++ safer a= nd safer, would it make sense to do the following?


int a; //value-initialized to 0

La= ter, some syntax like in D language could be provided:

=
int a =3D void;


The rationale = behind this change would be:

- an uninitialized va= riable that is replaced by these new semantics does not produce incorrect b= ehaviour.
- makes the language safer to use.

=
In the case where performance must be preserved, a compiler option wit= h the old semantics would be enough.

Would this ma= ke any sense or I am missing manu points? It looks to me that this could be= backwards-compatible
and the noly thing that could happen is a p= erformance bug, which can be solved replacing iniitialization or by a
=
compiler switch for large codebases.



--

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