Question

我正在尝试运行CPPReference's regex_search example：

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

int main()
{
    std::string lines[] = {"Roses are #ff0000",
                           "violets are #0000ff",
                           "all of my base are belong to you"};

    std::regex color_regex("#([a-f0-9]{2})"
                        "([a-f0-9]{2})"
                        "([a-f0-9]{2})");

    for (const auto &line : lines) {
        std::cout << line << ": " 
                  << std::regex_search(line, color_regex) << '\n';
    }   

    std::smatch color_match;
    for (const auto &line : lines) {
        std::regex_search(line, color_match, color_regex);
        std::cout << "matches for '" << line << "'\n";
        for (size_t i = 0; i < color_match.size(); ++i)
            std::cout << i << ": " << color_match[i] << '\n';
    }   
}

该程序使用Clang ++ 3.4-1ubuntu3和GCC 4.8.2编译，但立即运行会出现此错误：

terminate called after throwing an instance of 'std::regex_error'
  what():  regex_error
Aborted (core dumped)

This question表示问题与GCC有关，但与Clang编译会产生同样的问题。甚至使用以下命令在每一步显式传入库：

clang++ -stdlib=libstdc++ -std=c++11 -H -c regex.cpp -o object.o && clang++ -stdlib=libstdc++ object.o -o regex

在运行时导致错误，尽管第一个命令的输出的最后几行是：

.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_constants.h
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_error.h
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_cursor.h
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_nfa.h
... /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_nfa.tcc
.... /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/regex
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_compiler.h
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_grep_matcher.h
... /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex_grep_matcher.tcc
.... /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/regex
.. /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/bits/regex.h

...表示我的系统上存在相应的标题。

Answer 1

您仍然使用不完整的gcc标准库实现，甚至明确告诉clang将其与-stdlib=libstdc++一起使用。

clang附带的标准库实现为libc++，因此您需要-stdlib=libc++。

为什么这个程序在Clang或GCC下运行不正常？

1 个答案: