C ++ 11中支持的Unicode有多好？ [英] How well is Unicode supported in C++11?

问题描述

我读过并听说C ++ 11支持Unicode。有几个问题：

I've read and heard that C++11 supports Unicode. A few questions on that:

• C ++标准库支持Unicode有多好？


• std :: string 是否应该做什么？


• 如何使用？


• 潜在问题在哪里？

• How well does the C++ standard library support Unicode?
• Does std::string do what it should?
• How do I use it?
• Where are potential problems?

推荐答案

C ++标准库如何支持unicode？

How well does the C++ standard library support unicode?

可怕。

Unicode支持给我这个列表：

A quick scan through the library facilities that might provide Unicode support gives me this list:

• 字符串库


• 本地化库


• 输入/输出库


• 正则表达式库

• Strings library
• Localization library
• Input/output library
• Regular expressions library

第一个提供可怕的支持。

I think all but the first one provide terrible support. I'll get back to it in more detail after a quick detour through your other questions.

std： ：string 做什么呢？

是的。根据C ++标准，这是 std :: string 和它的兄弟应该做的

Yes. According to the C++ standard, this is what std::string and its siblings should do:

类模板 basic_string 描述了可以存储由不同数量的任意char样对象组成的序列的对象，序列的第一个元素位于零。

The class template basic_string describes objects that can store a sequence consisting of a varying number of arbitrary char-like objects with the first element of the sequence at position zero.

好吧， std :: string 这是否提供任何Unicode特定的功能？不。

Well, std::string does that just fine. Does that provide any Unicode-specific functionality? No.

应该吗？可能不会。 std :: string 作为 char 对象的序列很好。这很有用;唯一的烦恼是，它是一个非常低级别的文本和标准C ++不提供更高级别的视图。

Should it? Probably not. std::string is fine as a sequence of char objects. That's useful; the only annoyance is that it is a very low-level view of text and standard C++ doesn't provide a higher-level one.

如何使用它？

How do I use it?

使用它作为 char 对象的序列;

Use it as a sequence of char objects; pretending it is something else is bound to end in pain.

潜在的问题在哪里？

Where are potential problems?

整个地方？让我们看看...

All over the place? Let's see...

字符串库

字符串库提供给我们 basic_string ，这只是标准调用char-like objects的顺序。我称它们为代码单位。如果你想要一个高级的文本视图，这不是你要找的。这是一个适用于序列化/反序列化/存储的文本视图。

The strings library provides us basic_string, which is merely a sequence of what the standard calls "char-like objects". I call them code units. If you want a high-level view of text, this is not what you are looking for. This is a view of text suitable for serialization/deserialization/storage.

它还提供了C库中的一些工具，可用于弥合狭窄世界和Unicode世界： c16rtomb / mbrtoc16 和 c32rtomb mbrtoc32 。

It also provides some tools from the C library that can be used to bridge the gap between the narrow world and the Unicode world: c16rtomb/mbrtoc16 and c32rtomb/mbrtoc32.

本地化库

本地化库仍然相信那些char-like对象之一等于一个字符。这当然是愚蠢的，并且使得不可能得到很多东西在ASCII之外的一些小的Unicode子集上工作。

The localization library still believes that one of those "char-like objects" equals one "character". This is of course silly, and makes it impossible to get lots of things working properly beyond some small subset of Unicode like ASCII.

例如，考虑标准调用< locale> 标题中的便利界面：

Consider, for example, what the standard calls "convenience interfaces" in the <locale> header:

template <class charT> bool isspace (charT c, const locale& loc);
template <class charT> bool isprint (charT c, const locale& loc);
template <class charT> bool iscntrl (charT c, const locale& loc);
// ...
template <class charT> charT toupper(charT c, const locale& loc);
template <class charT> charT tolower(charT c, const locale& loc);
// ...

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