220 35592 <2a757acd-d7c7-490a-ac59-b590847940f6@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: zxuiji@gmail.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Rotational shift operator Date: Wed, 29 Nov 2017 04:04:07 -0800 (PST) Lines: 131 Approved: news@gmane.org Message-ID: <2a757acd-d7c7-490a-ac59-b590847940f6@isocpp.org> References: <69593098-e2cc-487e-bd14-9001b27aa7c1@isocpp.org> <15ffde291c8.2731.fb49792bc380c7e55e30f872b414f11c@gmail.com> <5165011.87BksPkTSX@tjmaciei-mobl1> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_19923_752179541.1511957047263" X-Trace: blaine.gmane.org 1511957050 20461 195.159.176.226 (29 Nov 2017 12:04:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 29 Nov 2017 12:04:10 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBCLLB64Y44NBBOGE7LIAKGQEP4KIOVQ@isocpp.org Wed Nov 29 13:04:05 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-vk0-f71.google.com ([209.85.213.71]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eK15u-0004sX-Oe for gclcip-std-proposals@m.gmane.org; Wed, 29 Nov 2017 13:04:02 +0100 Original-Received: by mail-vk0-f71.google.com with SMTP id s127sf689366vkf.13 for ; Wed, 29 Nov 2017 04:04:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to: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; bh=P4pZuU7W8mZH+ZbDm7FtU+G5BpO8jLbbinA4mdGW/qU=; b=VFf+XFU6HKG3aaCMGWbLtHgoBgzWc8GXC+jIWj0RD6UcyghlqexbZeCWZUKeDTVbYI qcSCu9mvQmPRocEK5apvFpSDrntfme/ABXCfVeNj06ox+c0nvATD9ij/o4h0QUD5DBvb /akGBtmNhGu5RNyMYAXik9N42DrJpMJheSvj6iAm08/3gwGDUFidw02/tyYoorXg9/ZL uu3imVblNKRfauzPNDbRtM3xglUuysNHkxk30j9npFv14RES+x0pqC7rzThNfZeQlEA3 /i1fvksdhKbdUkAlou320ASLF1t5UszyFVGStFgzpYKYE+TVv1TzOOwfZU+0esG2hNaL ULvQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to: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; bh=P4pZuU7W8mZH+ZbDm7FtU+G5BpO8jLbbinA4mdGW/qU=; b=VKqqkUQaui3ddc50PfFBzyHVgzNLzzCrvt2IKNXvrnobKc8Ktj4zrmGTjci6i9zXYO p77tQxn2QlQHM5U7q+NUX/26Y0gIPHHiirhC7rDz8sBFFqXN301u7BFOZMxNF+c/MN66 8rgz7IIcBLzSJkUdbeZm3eB9WTK2KFh1bkRBgUXRXjYG2PPII7LU4IYpisAQshobuthB akga17aVYyCjiq+O7UyslIMjHRaDGDgh1thZTmfVyIQpYN/JGW9YS5BxTo5x0vMrwv9i zYy5uiIpVDmf3p9CcOuFXJOe6OWzyUh4FChUnxV9qj2iv1n7nUIMhjfP0x6h16SqyyMS bzLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:x-original-sender:reply-to:precedence :mailing-list:list-id:x-spam-checked-in-group:list-post:list-help :list-archive:list-subscribe:list-unsubscribe; bh=P4pZuU7W8mZH+ZbDm7FtU+G5BpO8jLbbinA4mdGW/qU=; b=d85Nen8TK6XLlLkHfZh3x8tTqagsJrqpnKzcXo4aFIh02B4GgaDrROdL+icAhXgGmC vxvF8V30/RzesICJ4GLY8G72BclTz3unkmOR+oHN5I2dN2AtDUTlQSaxXYepeoP2BQtp kdlQCBZBInFkDM/smesxtacDKdOu4c3xnjqwPhK8Y12TtFiGmbHkW3QzLtVp/Y46s9rL oA0SS5mjegDsW02XDpXk6q6G8SgitMeIXW9IyG09NUr1JwqhdFtrvuY1oKO9cU0KlnUE kRc1BP/y344OnbXfA+eztF4L6sKcZds7ekuHLF1h6VqLC5CHefxa3hz5WKMCnBxNFGLb KR+Q== X-Gm-Message-State: AJaThX6mQh7Nb5dDrc4noTRfha51Lc0gO9euy2HVm3Xb+9fyFbJESLHL RcI1SVEUd8sXFlAWJLqyoSd7VQ== X-Google-Smtp-Source: AGs4zMa16cxTRk2W5boKJv8qecDchK6+huIc+itysTRrcpO/QwQp5nnWiqE/xVHDIPRit5zQ9hTFGw== X-Received: by 10.31.107.79 with SMTP id g76mr1166438vkc.88.1511957049954; Wed, 29 Nov 2017 04:04:09 -0800 (PST) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.176.72.48 with SMTP id b45ls4466847uad.2.gmail; Wed, 29 Nov 2017 04:04:08 -0800 (PST) X-Received: by 10.31.2.148 with SMTP id 142mr145888vkc.1.1511957048054; Wed, 29 Nov 2017 04:04:08 -0800 (PST) In-Reply-To: <5165011.87BksPkTSX@tjmaciei-mobl1> X-Original-Sender: zxuiji@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:35592 Archived-At: ------=_Part_19923_752179541.1511957047263 Content-Type: multipart/alternative; boundary="----=_Part_19924_392042206.1511957047263" ------=_Part_19924_392042206.1511957047263 Content-Type: text/plain; charset="UTF-8" On Wednesday, 29 November 2017 05:41:38 UTC, Thiago Macieira wrote: > > https://gcc.gnu.org/onlinedocs/gcc-3.4.2/gcc/Min-and-Max.html > > Deprecated, though. > What about the @ character? Any issues with that? On Wednesday, 29 November 2017 05:41:38 UTC, Thiago Macieira wrote: > > > I read further down about how pow() should have it's own operator, the > > immediate thought I had there was maybe ** & **= would work, old > compilers > > which aren't supposed to support the new standard would just fail to > > compile it anyway. As for the rotl/rotr thing I only don't like them > > because of A: how 1 needs to cast to be sure they get the part of the > > integer they want when they use it, neither can they be sure the bits > > rotate in the same way they would rotate on smaller/larger integer (e.g. > > 0x1 becoming 0x80000000 instead of 0x80) & B: One cannot apply the > rotation > > directly to the integer they are working with (like how "a += 1" is > faster > > than "a = a + 1") > > Faster to type, but not to execute. > > But I did not understand your reason for not liking. What cast is > necessary? > Can you give an example where using rotl without a cast would result in a > surprise or incorrect result? > rotl is not necessarily going to be a macro to operator usage, it can be a function using int/long/long long which means it falls to us to ensure the result not only that we receive is safe to place in the target variable but also the operation was done the way we would expect it to for the integer size we are working with. -- 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/2a757acd-d7c7-490a-ac59-b590847940f6%40isocpp.org. ------=_Part_19924_392042206.1511957047263 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
On Wednesday, 29 November 2017 05:41:38 UTC, Thiago Maciei= ra wrote:
https://gcc.gnu.org/onlinedocs/gcc-3.4.2/gcc/Min-= and-Max.html

Deprecated, though.

What about the @ character? Any issues= with that?

On Wednesday, 29 November 2017 05:41:3= 8 UTC, Thiago Macieira wrote:=C2=A0

> I read further down about how pow() should have it's own opera= tor, the
> immediate thought I had there was maybe ** & **=3D would work,= old compilers
> which aren't supposed to support the new standard would just f= ail to
> compile it anyway. As for the rotl/rotr thing I only don't lik= e them
> because of A: how 1 needs to cast to be sure they get the part of = the
> integer they want when they use it, neither can they be sure the b= its
> rotate in the same way they would rotate on smaller/larger integer= (e.g.
> 0x1 becoming 0x80000000 instead of 0x80) & B: One cannot apply= the rotation
> directly to the integer they are working with (like how "a += =3D 1" is faster
> than "a =3D a + 1")

Faster to type, but not to execute.

But I did not understand your reason for not liking. What cast is neces= sary?=20
Can you give an example where using rotl without a cast would result in= a=20
surprise or incorrect result?

rotl is not necessarily going to be a = macro to operator usage, it can be a function using int/long/long long whic= h means it falls to us to ensure the result not only that we receive is saf= e to place in the target variable but also the operation was done the way w= e would expect it to for the integer size we are working with.
= =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/2a757acd-d7c7-490a-ac59-b590847940f6= %40isocpp.org.
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