220 39480 article Path: news.gmane.org!.POSTED!not-for-mail From: Alexander Zaitsev Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: D1031R1 draft 1 LLFIO with proposed C++ object model and lifetime changes for mapped memory support Date: Wed, 1 Aug 2018 15:38:35 -0700 (PDT) Lines: 125 Approved: news@gmane.org Message-ID: References: <096f1d1c-3e2e-4df8-91ee-6f1cf4d31aad@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_156_1291085310.1533163115986" X-Trace: blaine.gmane.org 1533162992 26096 195.159.176.226 (1 Aug 2018 22:36:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 1 Aug 2018 22:36:32 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDGLZGV44EEBB3HMRDNQKGQE7UTORZI@isocpp.org Thu Aug 02 00:36:27 2018 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-yw0-f199.google.com ([209.85.161.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fkzjH-0006gX-86 for gclcip-std-proposals@m.gmane.org; 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Wed, 01 Aug 2018 15:38:37 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 2002:a25:2548:: with SMTP id l69-v6ls42412ybl.12.gmail; Wed, 01 Aug 2018 15:38:36 -0700 (PDT) X-Received: by 2002:a25:8448:: with SMTP id r8-v6mr1330ybm.2.1533163116502; Wed, 01 Aug 2018 15:38:36 -0700 (PDT) In-Reply-To: <096f1d1c-3e2e-4df8-91ee-6f1cf4d31aad@isocpp.org> X-Original-Sender: zamazan4ik@gmail.com 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:39480 Archived-At: ------=_Part_156_1291085310.1533163115986 Content-Type: multipart/alternative; boundary="----=_Part_157_1675232168.1533163115986" ------=_Part_157_1675232168.1533163115986 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =D0=B2=D1=82=D0=BE=D1=80=D0=BD=D0=B8=D0=BA, 31 =D0=B8=D1=8E=D0=BB=D1=8F 201= 8 =D0=B3., 22:08:27 UTC+3 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7=D0=BE=D0=B2=D0=B0= =D1=82=D0=B5=D0=BB=D1=8C Niall Douglas =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0= =D0=BB: > > So after many weeks of pondering and writing this outside of work each=20 > day, please find attached an early draft of revision 1 of P1031 destined= =20 > for San Diego. Changes since R0: > > - Wrote partial draft TS wording for deadline, handle, io_handle,=20 > mapped, mapped_view, native_handle_type and file_io_error. > - Added impact on the standard regarding potential changes to the C++= =20 > object model. > - Added impact on the standard regarding the proposed=20 > [[no_side_effects]] et al contracts attributes. > =20 > Note that the partial draft TS wording assumes Deterministic Exceptions += =20 > SG14 standard error object + in-progress _Fails calling convention=20 > implementation of P0709. > > I am very aware that modifying the C++ object and lifetime model is a hug= e=20 > ask of WG21. This is why memory maps are pure UB in current C++, despite= =20 > the fact that you can't implement dynamic memory allocation on the major= =20 > platforms without something like them. > > Please before you blow holes in my proposed changes, can you think of a= =20 > better alternative beforehand? I suspect that most "better alternatives"= =20 > have a very good technical reason why I couldn't choose them, but it woul= d=20 > do no harm to ask clever "stupid questions" at this stage in this=20 > proposal's lifecycle. Better out than in. > > My thanks in advance, especially for feedback on such a profound and=20 > complex part of the C++ standard. > > Niall > > Great proposal. One suggestion - possibly will be better to divide your=20 proposal into several proposals. My own wish - move contract=20 [[no_side_effects]] into another proposal. Because [[no_side_effects]] can= =20 help in another places for code optimization.=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. To view this discussion on the web visit https://groups.google.com/a/isocpp= ..org/d/msgid/std-proposals/fd17e3b3-00c9-4f2d-80b3-0f4f9490f388%40isocpp.or= g. ------=_Part_157_1675232168.1533163115986 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
=D0=B2=D1=82=D0=BE=D1=80=D0=BD=D0=B8=D0=BA, 31 =D0=B8=D1= =8E=D0=BB=D1=8F 2018 =D0=B3., 22:08:27 UTC+3 =D0=BF=D0=BE=D0=BB=D1=8C=D0=B7= =D0=BE=D0=B2=D0=B0=D1=82=D0=B5=D0=BB=D1=8C Niall Douglas =D0=BD=D0=B0=D0=BF= =D0=B8=D1=81=D0=B0=D0=BB:
So after many weeks of pondering and writing this outside of wo= rk each day, please find attached an early draft of revision 1 of P1031 des= tined for San Diego. Changes since R0:
  • Wrote partial draft TS w= ording for deadline, handle, io_handle, mapped, mapped_view, native_handle_= type and file_io_error.
  • Added impact on the standard regarding pote= ntial changes to the C++ object model.
  • Added impact on the standard= regarding the proposed [[no_side_effects]] et al contracts attributes.
    =
Note that the partial draft TS wording assumes Determi= nistic Exceptions + SG14 standard error object + in-progress _Fails calling= convention implementation of P0709.

I am very awa= re that modifying the C++ object and lifetime model is a huge ask of WG21. = This is why memory maps are pure UB in current C++, despite the fact that y= ou can't implement dynamic memory allocation on the major platforms wit= hout something like them.

Please before you blow h= oles in my proposed changes, can you think of a better alternative beforeha= nd? I suspect that most "better alternatives" have a very good te= chnical reason why I couldn't choose them, but it would do no harm to a= sk clever "stupid questions" at this stage in this proposal's= lifecycle. Better out than in.

My thanks in advan= ce, especially for feedback on such a profound and complex part of the C++ = standard.

Niall


Great proposal. One suggestion - possibly will be = better to divide your proposal into several proposals. My own wish - move c= ontract [[no_side_effects]] into another proposal. Because [[no_side_effect= s]] can help in another places for code optimization.=C2=A0

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+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/fd17e3b3-00c9-4f2d-80b3-0f4f9490f388= %40isocpp.org.
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