C++11 正则表达式是否适用于 UTF-8 字符串?

问题描述

如果我想将 C++11 的正则表达式与 unicode 字符串一起使用，它们会将 char* 用作 UTF-8 还是我必须将它们转换为 wchar_t* 字符串?

If I want to use C++11's regular expressions with unicode strings, will they work with char* as UTF-8 or do I have to convert them to a wchar_t* string?

推荐答案

您需要测试您的编译器和您正在使用的系统，但理论上，如果您的系统具有 UTF-8 语言环境，它将受到支持.以下测试在 Clang/OS X 上为我返回 true.

You would need to test your compiler and the system you are using, but in theory, it will be supported if your system has a UTF-8 locale. The following test returned true for me on Clang/OS X.

bool test_unicode()
{
    std::locale old;
    std::locale::global(std::locale("en_US.UTF-8"));

    std::regex pattern("[[:alpha:]]+", std::regex_constants::extended);
    bool result = std::regex_match(std::string("abcdéfg"), pattern);

    std::locale::global(old);

    return result;
}

注意:这是在 UTF-8 编码的文件中编译的.

NOTE: This was compiled in a file what was UTF-8 encoded.

为了安全起见，我还使用了一个带有显式十六进制版本的字符串.它也有效.

Just to be safe I also used a string with the explicit hex versions. It worked also.

bool test_unicode2()
{
    std::locale old;
    std::locale::global(std::locale("en_US.UTF-8"));

    std::regex pattern("[[:alpha:]]+", std::regex_constants::extended);
    bool result = std::regex_match(std::string("abcdxC3xA9""fg"), pattern);

    std::locale::global(old);

    return result;
}

更新 test_unicode() 仍然对我有用

$ file regex-test.cpp 
regex-test.cpp: UTF-8 Unicode c program text

$ g++ --version
Configured with: --prefix=/Applications/Xcode-8.2.1.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 8.0.0 (clang-800.0.42.1)
Target: x86_64-apple-darwin15.6.0
Thread model: posix
InstalledDir: /Applications/Xcode-8.2.1.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

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