220 27897 <36958399-1282-4cef-a12b-0439e176aeda@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: FrankHB1989 Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: Stabilize the numeric types in all platforms Date: Tue, 23 Aug 2016 04:31:20 -0700 (PDT) Lines: 159 Approved: news@gmane.org Message-ID: <36958399-1282-4cef-a12b-0439e176aeda@isocpp.org> References: <72b7e733-cb85-4f47-a09b-10611f04211b@isocpp.org> <18a39611-8088-4e04-be0a-bb1b7c485683@isocpp.org> <1706311.trY4MaExHO@tjmaciei-mobl1> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_1765_82022597.1471951880486" X-Trace: blaine.gmane.org 1471951890 20906 195.159.176.226 (23 Aug 2016 11:31:30 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 23 Aug 2016 11:31:30 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCTJVBPG3QIBBCXI6C6QKGQEPBMFKOQ@isocpp.org Tue Aug 23 13:31:24 2016 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 1bc9vP-00051O-KR for gclcip-std-proposals@m.gmane.org; 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Tue, 23 Aug 2016 04:31:24 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.36.41.80 with SMTP id p77ls4831283itp.4.gmail; Tue, 23 Aug 2016 04:31:22 -0700 (PDT) X-Received: by 10.36.111.147 with SMTP id x141mr814680itb.6.1471951881300; Tue, 23 Aug 2016 04:31:21 -0700 (PDT) In-Reply-To: <1706311.trY4MaExHO@tjmaciei-mobl1> X-Original-Sender: frankhb1989@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:27897 Archived-At: ------=_Part_1765_82022597.1471951880486 Content-Type: multipart/alternative; boundary="----=_Part_1766_1879929115.1471951880486" ------=_Part_1766_1879929115.1471951880486 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable =E5=9C=A8 2016=E5=B9=B48=E6=9C=8823=E6=97=A5=E6=98=9F=E6=9C=9F=E4=BA=8C UTC= +8=E4=B8=8B=E5=8D=8812:49:54=EF=BC=8CThiago Macieira=E5=86=99=E9=81=93=EF= =BC=9A > > On segunda-feira, 22 de agosto de 2016 21:36:12 PDT FrankHB1989 wrote:=20 > > OK, I should have said, they are not mandated *by the core language*,= =20 > or,=20 > > not guaranteed both built-in and portable.=20 > > They are mandated in a header that complements the core language. Just=20 > like=20 > , and , those types cannot be=20 > implemented by anyone except the compiler vendor.=20 > > Therefore, for all intents and purposes, the minimum-width and fast=20 > integer=20 > types are guaranteed to be portable.=20 > > The exact-width ones aren't guaranteed to be portable because their=20 > concept=20 > isn't portable. Some machines don't have 8-, 16-, 32- and 64-bit types=20 > (they=20 > could be multiples of 9 bits). Also note how int32_t is required to use= =20 > two's=20 > complement representation, which again excludes some machines.=20 > > Good point about 2's complements. However, all of these are what I have= =20 already known. I still wonder why these (at least partially) width-aware=20 types are not in the core language while traditional fundamental integer=20 types are still in it. In a systemic view of design, this is an=20 inappropriate inversion of abstraction layers -- all implementations in=20 reality build these fundamental types on some integer types with known=20 width provided by underlying specification, or just with the width=20 specified artificially. Since we always will have some exact width integers= =20 in the stacks of implementation, why not lift the uncertainty to the higher= =20 level? Though I don't think declaring `short` or `long` by users very=20 useful, but it gives us an opportunity to have the core language cleaner,= =20 with less confusion, meeting better to the principle of zero-cost=20 abstraction mentally, and being a little easier to implement. Or perhaps better keeping them all out of the core language? --=20 > Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org=20 > Software Architect - Intel Open Source Technology Center=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/36958399-1282-4cef-a12b-0439e176aeda%40isocpp.or= g. ------=_Part_1766_1879929115.1471951880486 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable


=E5=9C=A8 2016=E5=B9=B48=E6=9C=8823=E6=97=A5=E6=98= =9F=E6=9C=9F=E4=BA=8C UTC+8=E4=B8=8B=E5=8D=8812:49:54=EF=BC=8CThiago Maciei= ra=E5=86=99=E9=81=93=EF=BC=9A
O= n segunda-feira, 22 de agosto de 2016 21:36:12 PDT FrankHB1989 wrote:
> OK, I should have said, they are not mandated *by the core languag= e*, or,=20
> not guaranteed both built-in and portable.

They are mandated in a header that complements the core language. Just = like=20
<intializer_list>, <type_traits> and <limits>, those = types cannot be=20
implemented by anyone except the compiler vendor.

Therefore, for all intents and purposes, the minimum-width and fast int= eger=20
types are guaranteed to be portable.

The exact-width ones aren't guaranteed to be portable because their= concept=20
isn't portable. Some machines don't have 8-, 16-, 32- and 64-bi= t types (they=20
could be multiples of 9 bits). Also note how int32_t is required to use= two's=20
complement representation, which again excludes some machines.

Good point about 2's complements. However, all of= these are what I have already known. I still wonder why these (at least pa= rtially) width-aware types are not in the core language while traditional f= undamental integer types are still in it. In a systemic view of design, this is an inappropriate = inversion of abstraction layers -- all implementations in reality build the= se fundamental types on some integer types with known width provided by und= erlying specification, or just with the width specified artificially. Since= we always will have some exact width integers in the stacks of implementat= ion, why not lift the uncertainty to the higher level? Though I don't t= hink declaring `short` or `long` by users very useful, but it gives us an o= pportunity to have the core language cleaner, with less confusion, meeting = better to the principle of zero-cost abstraction mentally, and being a litt= le easier to implement.
Or perhaps better keeping them all out of the co= re language?


--=20
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
=C2=A0 =C2=A0Software Architect - Intel Open Source Technology Center

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