220 13366 <6cc0543b-ce2b-4cf3-bc18-bf1a5be8a270@isocpp.org> article Path: news.gmane.org!not-for-mail From: Douglas Boffey Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: proposal: deprecate failure to return (without annotation) Date: Tue, 30 Sep 2014 02:07:43 -0700 (PDT) Lines: 96 Approved: news@gmane.org Message-ID: <6cc0543b-ce2b-4cf3-bc18-bf1a5be8a270@isocpp.org> References: <2106187.KAVOBzdsgo@tjmaciei-mobl4> <7890243.H6e3ul2NkU@tjmaciei-mobl4> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_4142_433762223.1412068064024" X-Trace: ger.gmane.org 1412068078 26585 80.91.229.3 (30 Sep 2014 09:07:58 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 30 Sep 2014 09:07:58 +0000 (UTC) Cc: gmisocpp@gmail.com To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDSIZVXVVUFBBYHFVGQQKGQE35ECECA@isocpp.org Tue Sep 30 11:07:52 2014 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-pd0-f199.google.com ([209.85.192.199]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1XYtPR-0000zC-C9 for gclcip-std-proposals@m.gmane.org; Tue, 30 Sep 2014 11:07:49 +0200 Original-Received: by mail-pd0-f199.google.com with SMTP id ft15sf21751371pdb.6 for ; Tue, 30 Sep 2014 02:07:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe:content-type; bh=o0O93zUww6qc5xOBsLA+KdUqgGSRYAdmTXbBl9vNGTA=; b=IfKby1hps3umSBJszhm5srf/DCYCkUzktV2IVwvQ0p4TEXjFzB81XOfUyo/aJizrdu GL/wIDYZ4CjBNYMPg07K8HvbJHdD5LnuOABPu4I/19rtSeyTHveRwT4zZRfZg/V/XAYF nj4XJMg9i/TaoXiGiOCATEAOIFM11HVT9I81X9St1vDshFSAwRORti+z0kJNMeTwA7g0 GDIiPJ3BlophO+ZJ+kgbCBsmUVBh8fp3Xf9Yky6d4S+uVbmrI5zHgoMj+Ph3N5F3INsW 8ZTwlWOpQKSroG5fv0EqE7T+16C09KYjX7Z3ZN6JMCRHloH82febaCidnuZNbah42ROc ed3A== 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:cc:message-id:in-reply-to :references:subject:mime-version:x-original-sender:reply-to :precedence:mailing-list:list-id:list-post:list-help:list-archive :list-subscribe:list-unsubscribe:content-type; bh=o0O93zUww6qc5xOBsLA+KdUqgGSRYAdmTXbBl9vNGTA=; b=drO8XsGc1kNM8RbYnZOLAS7I+L3z3TYKBIBsFMBeX8ws+rXQDXjV4znzKWr71ndvGS 628H/G0PIk8hKbEUkMpcxaw4LgGjbfG41gmdT6Os3WoAMvqMd2bSdKVcOCIDAmi3rEZh J8vuKqNoaLfRTjK72W9sya1+oKOPiAZLptyslTzZ1eHdhtLg8tUvEy5ZUnYk9dmjIO8A V98CFJdKPgN0KFGJC7dbbGHVF0CQ+AV0RcPIL9YhquTp1KSCqFOqY1Xe/RIIkHLbFUAv 5xfAwbFzT/3EOQP3woZb/DLTS6oStcc2gMMnuDn8gviAGZXugcJBKtZoDDH4ixm1Xsal 713Q== X-Gm-Message-State: ALoCoQmnFa0JRFCd6mHBxFcNjWw5vOxAuw+sif/Uchrgj5HYWgrmGgANmTQmlFcdw0kcTnzadT8b X-Received: by 10.66.196.70 with SMTP id ik6mr39961279pac.44.1412068065482; Tue, 30 Sep 2014 02:07:45 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.140.23.240 with SMTP id 103ls529603qgp.45.gmail; Tue, 30 Sep 2014 02:07:44 -0700 (PDT) X-Received: by 10.140.102.110 with SMTP id v101mr10755qge.6.1412068064776; Tue, 30 Sep 2014 02:07:44 -0700 (PDT) In-Reply-To: X-Original-Sender: Douglas.Boffey@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:13366 Archived-At: ------=_Part_4142_433762223.1412068064024 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tuesday, 30 September 2014 00:28:04 UTC+1, gmis...@gmail.com wrote: > > // noreturn works like this: > // 1. Compiler attempts to verify the no_return block is unreachable, > // if it unreachable, no code is generated and no warning is issued. > // 2. If compiler can't verify the block is unreachable, a warning is= =20 > issued > // and the code inside the block is generated. > // 3. If that code cannot be verified as not returning, > // compiler injects code to ensure there is no way to return.=20 > // i.e. code to ensure std::terminate() is called the end of the block. > try > { > app_exit();=20 > } > catch(...) > { > // Would be nice if compiler offered the ability to=20 > inject __debug_break here too in some situations like for debug builds. > //.Then we can more easily diagnose the code where we made a=20 > wrong assumption. > std::terminate(); > } =20 > } > > Thoughts? > =20 Hmm. std::terminate injected into production code without being=20 explicity stated? I don=E2=80=99t think I=E2=80=99d like that=E2=80=94for = some production code,=20 premature termination is not an option.=20 --=20 ---=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. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. ------=_Part_4142_433762223.1412068064024 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

On Tuesday, 30 September 2014 00:28:04 UTC+1, gmis...@= gmail.com wrote:
  = // noreturn works like this:
  // 1. Compiler attempts to verify th= e no_return block is unreachable,
  // if it unreachable, no code i= s generated and no warning is issued.
  // 2. If compiler can'= t verify the block is unreachable, a warning is issued
  // and the= code inside the block is generated.
  // 3. If that code= cannot be verified as not returning,
  // compiler injects co= de to ensure there is no way to return.
  // i.e. code to e= nsure std::terminate() is called the end of the block.
  try
&nb= sp; {
      app_exit();
  }
  = catch(...)
  {
    // Would be nice if com= piler offered the ability to inject __debug_break here = too in some situations like for debug builds.
    = //.Then we can more easily diagnose the code where we made a wron= g assumption.
    std::terminate();
  } = ;
}

Thoughts?
&nb= sp;
Hmm.  std::terminate injected into production code witho= ut being explicity stated?  I don=E2=80=99t think I=E2=80=99= d like that=E2=80=94for some production code, premature termination is not = an option. 

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