From -3772169048382300166 X-Google-Language: ENGLISH,ASCII Path: g2news2.google.com!news2.google.com!npeer03.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!news.alt.net!frodo.cs.rpi.edu!not-for-mail From: Mathias Gaunard Newsgroups: comp.std.c++ Subject: Re: C++0x string conversions, etc. Date: Fri, 28 Aug 2009 11:09:47 CST Organization: http://groups.google.com Lines: 31 Sender: cppmods@cs.rpi.edu Approved: stephen.clamage@sun.com Message-ID: References: <7.0.0.16.2.20090826221507.040f5928@aristeia.com> NNTP-Posting-Host: netlab.cs.rpi.edu Content-Type: text/plain; charset=ISO-8859-1 To: (Usenet) Return-Path: X-Original-Date: Thu, 27 Aug 2009 21:41:01 -0700 (PDT) X-Submission-Address: std-c++@netlab.cs.rpi.edu Xref: g2news2.google.com comp.std.c++:1322 On 28 ao�t, 00:45, Scott Meyers wrote: > - If I have a pointer p of type char16_t* that points to a string encoded > using UTF-16 (a multibyte format) and I say ++p, does p move forward a > single (multibyte) character or a fixed number of machine bytes? In > other words, can a compiler generate a fixed increment for the value of p > (as it would be able to do with a char* pointer), or must the value of > the increment be determined at runtime based on the character p points > to? UTF-16 is a encoding for the Unicode character set that encodes a code point as one or two 16-bit code units. Pointers to char16_t don't behave any differently than pointers to anything else. If you increment a pointer to a T, the memory address held in the pointer is increased by sizeof(T) bytes. So that means that if you increment a pointer to a char16_t, you are now at the next UTF-16 code unit, not necessarily at the next code point. If you want smart iteration of UTF-8 or UTF-16 ranges, you need a conversion facility defined in terms of range adapters, not codecvt facets. -- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@netlab.cs.rpi.edu] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ]