如何在Windows控制台上输出Unicode字符串 [英] How to Output Unicode Strings on the Windows Console

问题描述

已经有一些与此问题有关的问题。我认为我的问题有所不同，因为我没有实际问题，只是出于学术兴趣而提出的。我知道Windows的UTF-16实施有时与Unicode标准（例如排序规则）相矛盾，或更接近于旧的UCS-2，而不是UTF-16，但出于以下原因，在此我将保留 UTF-16术语

there are already a few questions relating to this problem. I think my question is a bit different because I don't have an actual problem, I'm only asking out of academic interest. I know that Windows's implementation of UTF-16 is sometimes contradictory to the Unicode standard (e.g. collation) or closer to the old UCS-2 than to UTF-16, but I'll keep the "UTF-16" terminology here for reasons of simplicity.

背景：在Windows中，一切都是UTF-16。无论您是要处理内核，图形子系统，文件系统还是其他任何事物，都可以传递UTF-16字符串。 Unix上没有语言环境或字符集。为了与中世纪版本的Windows兼容，有一种叫做代码页的东西已经过时，但仍受支持。 AFAIK，只有一个正确且不作废的功能可以将字符串写入控制台，即 WriteConsoleW ，它需要一个UTF-16字符串。同样，类似的讨论也适用于输入流，我也将忽略。

Background: In Windows, everything is UTF-16. Regardless of whether you're dealing with the kernel, the graphics subsystem, the filesystem or whatever, you're passing UTF-16 strings. There are no locales or charsets in the Unix sense. For compatibility with medieval versions of Windows, there is a thing called "codepages" that is obsolete but nonetheless supported. AFAIK, there is only one correct and non-obsolete function to write strings to the console, namely WriteConsoleW, which takes an UTF-16 string. Also, a similar discussion applies to input streams, which I'll ignore, too.

但是，我认为这代表了Windows API的设计缺陷：可以用于写入所有流对象（文件，管道，控制台等）的通用函数，称为 WriteFile ，但是此函数是面向字节的，并且不接受UTF- 16弦。该文档建议使用 WriteConsoleW 进行控制台输出（面向文本），使用 WriteFile 进行其他所有操作（面向字节）。 。由于控制台流和文件对象均由内核对象句柄表示，并且控制台流可以重定向，因此每次写入标准输出流时都必须调用一个函数，以检查句柄是代表控制台流还是文件，从而破坏了多态性。 OTOH，我确实认为Windows在文本字符串和原始字节之间的分隔（在许多其他系统（如Java或Python）中得到了体现）在概念上优于Unix的 char * 方法

However, I think this represents a design flaw in the Windows API: there is a generic function that can be used to write to all stream objects (files, pipes, consoles…) called WriteFile, but this function is byte-oriented and doesn't accept UTF-16 strings. The documentation suggests using WriteConsoleW for console output, which is text oriented, and WriteFile for everything else, which is byte oriented. Since both console streams and file objects are represented by kernel object handles and console streams can be redirected, you have to call a function for every write to a standard output stream that checks whether the handle represents a console stream or a file, breaking polymorphy. OTOH, I do think that Windows's separation between text strings and raw bytes (which is mirrored in many other systems like Java or Python) is conceptually superior to Unix's char* approach that ignores encodings and doesn't distinguish between strings and byte arrays.

所以我的问题是：在这种情况下该怎么办？为什么即使在Microsoft自己的库中也无法解决此问题？ .NET Framework和C和C ++库似乎都遵循过时的代码页模型。您将如何设计Windows API或应用程序框架来解决此问题？

So my questions are: What to do in this situation? And why isn't this problem solved even in Microsoft's own libraries? Both the .NET Framework and the C and C++ libraries seem to adhere to the obsolete codepage model. How would you design the Windows API or an application framework to circumvent this issue?

我认为一般问题（不容易解决）是所有库都假定所有流都是面向字节的，并在此基础上实现面向文本的流。但是，我们看到Windows在OS级别上确实具有特殊的面向文本的流，并且库无法对此进行处理。因此，无论如何我们都必须对所有标准库进行重大更改。一种快速而肮脏的方法是将控制台视为仅接受一种编码的特殊的面向字节的流。这仍然要求必须规避C和C ++标准库，因为它们没有实现 WriteFile / WriteConsoleW 开关。

I think that the general problem (which is not easy to solve) is that all libraries assume that all streams are byte-oriented, and implement text-oriented streams on top of that. However, we see that Windows does have special text-oriented streams on the OS level, and the libraries are unable to deal with this. So in any case we must introduce significant changes to all standard libraries. A quick and dirty way would be to treat the console as a special byte-oriented stream that accepts only one encoding. This still requires that the C and C++ standard libraries must be circumvented because they don't implement the WriteFile/WriteConsoleW switch. Is that correct?

推荐答案

我/我们在大多数（跨平台）应用程序/项目中使用的一般策略是：我们只使用UTF-8（我的意思是真正的标准）无处不在。我们使用std :: string作为容器，我们只是将一切解释为UTF8。而且我们还以这种方式处理所有文件IO，即我们希望使用UTF8并保存UTF8。如果我们从某个地方得到一个字符串并且我们知道它不是UTF8，我们将其转换为UTF8。

The general strategy I/we use in most (cross platform) applications/projects is: We just use UTF-8 (I mean the real standard) everywhere. We use std::string as the container and we just interpret everything as UTF8. And we also handle all file IO this way, i.e. we expect UTF8 and save UTF8. In the case when we get a string from somewhere and we know that it is not UTF8, we will convert it to UTF8.

最常见的情况是偶然碰到WinUTF16用于文件名。因此，对于每个文件名处理，我们将始终将UTF8字符串转换为WinUTF16。

The most common case where we stumble upon WinUTF16 is for filenames. So for every filename handling, we will always convert the UTF8 string to WinUTF16. And also the other way if we search through a directory for files.

控制台在我们的Windows版本中并没有真正使用（在Windows版本中，所有控制台输出都是包装成文件）。由于我们到处都有UTF8，因此控制台输出也是UTF8，这对于大多数现代系统都很好。而且Windows控制台日志文件在UTF8中具有其内容，Windows上的大多数文本编辑器都可以毫无问题地读取它。

The console isn't really used in our Windows build (in the Windows build, all console output is wrapped into a file). As we have UTF8 everywhere, also our console output is UTF8 which is fine for most modern systems. And also the Windows console log file has its content in UTF8 and most text-editors on Windows can read that without problems.

如果我们更多地使用WinConsole，并且会非常在意所有特殊字符是否正确显示，我们可能会编写一些自动管道处理程序，将其安装在 fileno = 0 和实际的之间stdout ，它将按照您的建议使用 WriteConsoleW （如果确实没有更简单的方法）。

If we would use the WinConsole more and if we would care a lot that all special chars are displayed correctly, we maybe would write some automatic pipe handler which we install in between fileno=0 and the real stdout which will use WriteConsoleW as you have suggested (if there is really no easier way).

如果您想知道如何实现这种自动管道处理程序：我们已经为所有类似POSIX的系统实现了这种方法。该代码可能无法在Windows上正常运行，但我认为应该可以移植它。我们当前的管道处理程序类似于 tee 所做的事情。即如果您执行 cout<< 你好<< endl ，它将同时打印在 stdout 和某些日志文件中。查看代码，如果您对此感兴趣的话。

If you wonder about how to realize such automatic pipe handler: We have implemented such thing already for all POSIX-like systems. The code probably doesn't work on Windows as it is but I think it should be possible to port it. Our current pipe handler is similar to what tee does. I.e. if you do a cout << "Hello" << endl, it will both be printed on stdout and in some log-file. Look at the code if you are interested how this is done.

这篇关于如何在Windows控制台上输出Unicode字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！