220 29342 <5933359a-3f59-33df-10db-e643bfa39c55@honermann.net> article Path: news.gmane.org!.POSTED!not-for-mail From: Tom Honermann Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Re: std::byte thoughts Date: Wed, 2 Nov 2016 10:01:49 -0400 Lines: 74 Approved: news@gmane.org Message-ID: <5933359a-3f59-33df-10db-e643bfa39c55@honermann.net> References: <7da80620-e4bd-40eb-a4ec-4f3c2dcb2c98@isocpp.org> <1549171.TC16PSHVVd@tjmaciei-mobl1> <2350841.Z7lUCKSumT@tjmaciei-mobl1> <3e64b220-79ae-4108-ba1c-9785494fc434@isocpp.org> <97ebfc84-c5a3-eaf5-efcb-c1bdf9b507a5@gmail.com> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="------------9BBFD717F93BBE58E2A94ABE" X-Trace: blaine.gmane.org 1478095398 31970 195.159.176.226 (2 Nov 2016 14:03:18 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 2 Nov 2016 14:03:18 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 To: std-proposals@isocpp.org Original-X-From: std-proposals+bncBDBNXSHG6UDBBC7E47AAKGQE6V4HNYA@isocpp.org Wed Nov 02 15:03:14 2016 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-wm0-f72.google.com ([74.125.82.72]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1c1w7t-0005Hq-Ap for gclcip-std-proposals@m.gmane.org; Wed, 02 Nov 2016 15:02:49 +0100 Original-Received: by mail-wm0-f72.google.com with SMTP id u144sf11075565wmu.1 for ; Wed, 02 Nov 2016 07:02:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:x-original-sender:x-original-authentication-results :reply-to:precedence:mailing-list:list-id:x-spam-checked-in-group :list-post:list-help:list-archive:list-subscribe:list-unsubscribe; bh=Gdt9sWD1/YyrDxjMkKP96AEA1GhPLen+rhzC7rkug1M=; b=2J3Y4e4U95q2Uyc28C78c9wzWn89tHhvAE1HNfb4aQwYD7QutLxXy4tum79LbJDaHU srU/HuyMp86+w6jqU0LiisfQH6TM9J3WNavJT51ch5DCM2zoJ5mKDFOU8hPxlbyYsFus M0yLCRniAkkwTsXqTip+4cTwEKO7S4SyodG3p8CDM/2us8dNszLMWFf/pwbKDgHndKXu K6ByK0gH0HsYHE5fqYH9tCYfqNXiIoaGFcUBHKH6N8kYNHDxAjexADm591O9YjK18D6i yPpkQBwPFE3AX/TK70kvf9V87UmXvHafHwPCwzQYE2Ra833par3QUk0W198posqFzsuG BH5A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:x-original-sender :x-original-authentication-results:reply-to:precedence:mailing-list :list-id:x-spam-checked-in-group:list-post:list-help:list-archive :list-subscribe:list-unsubscribe; bh=Gdt9sWD1/YyrDxjMkKP96AEA1GhPLen+rhzC7rkug1M=; b=R0rB80FlP8HVASFY3x5QEn/WSC/nZ5/oUgtil+MIJw82NBS1Apg8R0IT62F++HrNnE jFpDHBhyjIyf39Ryv8kvyNK8P89NvT4o2ZCg4OnNMUvy4BeqBeOeLs9uWKY21CXkJT7e 19sLujaMCJjCaM23a9cfTNkEDaJCaThIlzVFhiNrbbe/Y1RLlLoDuKCxhlyY+aM3rjCo I6kXng82+5xk7YxQS+0f7l+BjbOQkqFnR5GccIk8oB/QRd0rb91Nm8H4Hcke7K78O3CJ z8ZEfgpTUN81hwl6O8sBDp6qa2DFElkzIyji+agqnuf0nnVSw7fdqXg30zNLePnnSNP5 g5EA== X-Gm-Message-State: ABUngvfk6yjLIbI16CKjWMtpyZy0+TQn3uyZCOVSpJ0puJVWH7kXTPLgj1jJ5AG0phrH0w== X-Received: by 10.194.69.133 with SMTP id e5mr191686wju.8.1478095372370; Wed, 02 Nov 2016 07:02:52 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.28.150.14 with SMTP id y14ls427847wmd.27.canary-gmail; Wed, 02 Nov 2016 07:02:51 -0700 (PDT) X-Received: by 10.194.175.166 with SMTP id cb6mr3051648wjc.84.1478095371177; Wed, 02 Nov 2016 07:02:51 -0700 (PDT) Original-Received: from smtp123.iad3a.emailsrvr.com (smtp123.iad3a.emailsrvr.com. [173.203.187.123]) by mx.google.com with ESMTPS id z13si37846156wmz.143.2016.11.02.07.02.50 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Nov 2016 07:02:50 -0700 (PDT) Received-SPF: neutral (google.com: 173.203.187.123 is neither permitted nor denied by best guess record for domain of tom@honermann.net) client-ip=173.203.187.123; Original-Received: from smtp8.relay.iad3a.emailsrvr.com (localhost [127.0.0.1]) by smtp8.relay.iad3a.emailsrvr.com (SMTP Server) with ESMTP id CAF1855A4 for ; Wed, 2 Nov 2016 10:01:49 -0400 (EDT) X-Auth-ID: tom@honermann.net Original-Received: by smtp8.relay.iad3a.emailsrvr.com (Authenticated sender: tom-AT-honermann.net) with ESMTPSA id B818E558B for ; Wed, 2 Nov 2016 10:01:49 -0400 (EDT) X-Sender-Id: tom@honermann.net Original-Received: from [192.168.1.16] (pool-71-176-249-9.rcmdva.fios.verizon.net [71.176.249.9]) (using TLSv1.2 with cipher DHE-RSA-AES128-SHA) by 0.0.0.0:587 (trex/5.7.7); Wed, 02 Nov 2016 10:01:49 -0400 In-Reply-To: <97ebfc84-c5a3-eaf5-efcb-c1bdf9b507a5@gmail.com> X-Original-Sender: tom@honermann.net X-Original-Authentication-Results: mx.google.com; spf=neutral (google.com: 173.203.187.123 is neither permitted nor denied by best guess record for domain of tom@honermann.net) smtp.mailfrom=tom@honermann.net 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:29342 Archived-At: This is a multi-part message in MIME format. --------------9BBFD717F93BBE58E2A94ABE Content-Type: text/plain; charset=UTF-8; format=flowed On 11/02/2016 05:02 AM, Andrey Semashev wrote: > Assuming that code units are always positive (which I don't think is > mandated anywhere, but let's keep things sane), I don't know of any encodings that specify negative values for code units or code points. However, the mapping of UTF-8 code units to char results in negative code unit values in UTF-8 strings for implementations that use a signed 8-bit char. So, in practice, sanity does not always prevail. This is one of the motivations for P0482R0 . Tom. -- 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/5933359a-3f59-33df-10db-e643bfa39c55%40honermann.net. --------------9BBFD717F93BBE58E2A94ABE Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
On 11/02/2016 05:02 AM, Andrey Semashev wrote:
Assuming that code units are always positive (which I don't think is mandated anywhere, but let's keep things sane),

I don't know of any encodings that specify negative values for code units or code points.=C2=A0 However, the mapping of UTF-8 code units to char results in negative code unit values in UTF-8 strings for implementations that use a signed 8-bit char.=C2=A0 So, in practice, sanity does not always prevail.=C2=A0 This is one of the motivations fo= r P0482R0.

Tom.

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