basic_regex使用char32_t抛出bad_cast [英] basic_regex throws bad_cast with char32_t

问题描述

以下代码为什么会生成 std :: bad_cast 异常?

Why does the following code generate std::bad_cast exception?

#include <iostream>
#include <regex>
#include <string>

int main()
{
    std::basic_string<char32_t> reg = U"^\\w";

    try
    {
        std::basic_regex<char32_t> tagRegex(reg);
    }
    catch(std::exception &e)
    {
        std::cout << e.what() << std::endl;
    }

    return 0;
}

为方便起见，此示例在Ideone上: https://ideone.com/Saea88

This sample on Ideone for convenience: https://ideone.com/Saea88

使用 char 或 wchar 而不是 char32_t 运行但不会抛出错误(证明:

Using char or wchar instead of char32_t runs without throwing though (proof: https://ideone.com/OBlXed).

推荐答案

您可以在此处找到:

要将std :: basic_regex与其他字符类型(例如char32_t)一起使用，必须使用用户提供的特征类.

To use std::basic_regex with other character types (for example, char32_t), a user-provided trait class must be used.

所以您必须实现 std :: regex_traits< char32_t>

并查看为什么对此没有定义，请参见此处:

and to see why there is no definition for it see here: Why is there no definition for std::regex_traits<char32_t> (and thus no std::basic_regex<char32_t>) provided?

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