Macos 链接到libc++；编译增压

我仍然在努力使用libc++和boost

我使用libc++编译了boost，如下所示：

现在，我在我的一台机器上看到了这个编译错误，而另一台机器编译的代码非常精确。它们都有相同的编译器版本，环境变量也相同

以下是错误：

Linking CXX executable main
/opt/local/bin/cmake -E cmake_link_script CMakeFiles/main.dir/link.txt --verbose=1
/usr/bin/clang++    -arch x86_64 -Wl,-search_paths_first -Wl,-headerpad_max_install_names -stdlib=libc++ CMakeFiles/main.dir/main.cpp.o  -o main  /usr/lib/libpython2.7.dylib /opt/local/lib/libboost_program_options-mt-d.a /opt/local/lib/libboost_filesystem-mt-d.a /opt/local/lib/libboost_system-mt.a /opt/local/lib/libboost_date_time-mt.a /opt/local/lib/libboost_python-mt.a /opt/local/lib/libboost_log-mt.a /opt/local/lib/libboost_thread-mt.a 
Undefined symbols for architecture x86_64:
  "__ZNSt3__112basic_stringIwNS_11char_traitsIwEENS_9allocatorIwEEE6appendIPwEENS_9enable_ifIXsr21__is_forward_iteratorIT_EE5valueERS5_E4typeES9_S9_", referenced from:
      std::__1::basic_string<wchar_t, std::__1::char_traits<wchar_t>, std::__1::allocator<wchar_t> > boost::detail::convert<wchar_t, char, boost::_bi::bind_t<std::__1::codecvt_base::result, boost::_mfi::cmf7<std::__1::codecvt_base::result, std::__1::codecvt<wchar_t, char, __mbstate_t>, __mbstate_t&, char const*, char const*, char const*&, wchar_t*, wchar_t*, wchar_t*&>, boost::_bi::list8<boost::_bi::value<std::__1::codecvt<wchar_t, char, __mbstate_t> const*>, boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::arg<4>, boost::arg<5>, boost::arg<6>, boost::arg<7> > > >(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, boost::_bi::bind_t<std::__1::codecvt_base::result, boost::_mfi::cmf7<std::__1::codecvt_base::result, std::__1::codecvt<wchar_t, char, __mbstate_t>, __mbstate_t&, char const*, char const*, char const*&, wchar_t*, wchar_t*, wchar_t*&>, boost::_bi::list8<boost::_bi::value<std::__1::codecvt<wchar_t, char, __mbstate_t> const*>, boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::arg<4>, boost::arg<5>, boost::arg<6>, boost::arg<7> > >) in libboost_program_options-mt-d.a(convert.o)
  "__ZNSt3__112basic_stringIcNS_11char_traitsIcEENS_9allocatorIcEEE6appendIPcEENS_9enable_ifIXsr21__is_forward_iteratorIT_EE5valueERS5_E4typeES9_S9_", referenced from:
      std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > boost::detail::convert<char, wchar_t, boost::_bi::bind_t<std::__1::codecvt_base::result, boost::_mfi::cmf7<std::__1::codecvt_base::result, std::__1::codecvt<wchar_t, char, __mbstate_t>, __mbstate_t&, wchar_t const*, wchar_t const*, wchar_t const*&, char*, char*, char*&>, boost::_bi::list8<boost::_bi::value<std::__1::codecvt<wchar_t, char, __mbstate_t> const*>, boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::arg<4>, boost::arg<5>, boost::arg<6>, boost::arg<7> > > >(std::__1::basic_string<wchar_t, std::__1::char_traits<wchar_t>, std::__1::allocator<wchar_t> > const&, boost::_bi::bind_t<std::__1::codecvt_base::result, boost::_mfi::cmf7<std::__1::codecvt_base::result, std::__1::codecvt<wchar_t, char, __mbstate_t>, __mbstate_t&, wchar_t const*, wchar_t const*, wchar_t const*&, char*, char*, char*&>, boost::_bi::list8<boost::_bi::value<std::__1::codecvt<wchar_t, char, __mbstate_t> const*>, boost::arg<1>, boost::arg<2>, boost::arg<3>, boost::arg<4>, boost::arg<5>, boost::arg<6>, boost::arg<7> > >) in libboost_program_options-mt-d.a(convert.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [main] Error 1
make[1]: *** [CMakeFiles/main.dir/all] Error 2
make: *** [all] Error 2

另一方面，在编译良好的机器上，我可以“看到”libc++的速度。在Xcode中使用时，速度非常快，使用libc++完成代码非常惊人

---

但在我进一步享受之前，我真的想弄清这件事的真相…

我刚刚解决了我的问题。这是因为Boost没有正确编译，因为在我的另一台机器中，bjam无法识别libiconv。我想它没有被识别的原因可能是因为我安装了macport。在我卸载所有macport的东西后，bjam可以立即识别libiconv并在libc++下正确构建boost（信号除外），但这没关系。

快速测试：将

-std=c++11

添加到命令行是否有帮助？在缺少的符号中引用

enable_if

，让我想知道……你的意思是将该标志添加到链接器，对吗？我想在那台失败的机器上，libiconv可能有点混乱。我的boost库没有在那台机器上正确构建。我注意到不同的是iconv（分离）在故障机器上不是。不知道为什么我要删除所有macport的东西并重建boost，我会在完成后更新。

#include <iostream>
#include <string>
#include <tuple>
#include <mutex>
#include <boost/filesystem.hpp>
#include <boost/system/system_error.hpp>
#include <boost/system/error_code.hpp>
#include <boost/program_options.hpp>
#include <CoreFoundation/CoreFoundation.h>
namespace po = boost::program_options;
int main(int ac, char* av[])
{
    using namespace std;
    std::mutex mymutex;
    std::tuple<int, int ,char> mytuple;

    boost::filesystem::path mypath("/usr/local/bin");
    boost::filesystem::path agaain("/usr");

    try {

        po::options_description desc("Allowed options");
        desc.add_options()
            ("help", "produce help message")
            ("compression", po::value<double>(), "set compression level")
        ;

        po::variables_map vm;        
        po::store(po::parse_command_line(ac, av, desc), vm);
        po::notify(vm);    

        if (vm.count("help")) {
            cout << desc << "\n";
            return 0;
        }

        if (vm.count("compression")) {
            cout << "Compression level was set to " 
                 << vm["compression"].as<double>() << ".\n";
        } else {
            cout << "Compression level was not set.\n";
        }
    }
    catch(exception& e) {
        cerr << "error: " << e.what() << "\n";
        return 1;
    }
    catch(...) {
        cerr << "Exception of unknown type!\n";
    }

    return 0;
}

chen@work:build$ make VERBOSE=1
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cd /Users/chen/Code/clang/build && /opt/local/bin/cmake -E cmake_depends "Unix Makefiles" /Users/chen/Code/clang /Users/chen/Code/clang /Users/chen/Code/clang/build /Users/chen/Code/clang/build /Users/chen/Code/clang/build/CMakeFiles/main.dir/DependInfo.cmake --color=
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Dependee "/Users/chen/Code/clang/build/CMakeFiles/CMakeDirectoryInformation.cmake" is newer than depender "/Users/chen/Code/clang/build/CMakeFiles/main.dir/depend.internal".
Scanning dependencies of target main
make -f CMakeFiles/main.dir/build.make CMakeFiles/main.dir/build
/opt/local/bin/cmake -E cmake_progress_report /Users/chen/Code/clang/build/CMakeFiles 1
[100%] Building CXX object CMakeFiles/main.dir/main.cpp.o
/usr/bin/clang++    -arch x86_64 -I/Users/chen/Code/clang -I/opt/local/include -I/System/Library/Frameworks/Python.framework/Headers -I/Users/chen/Code/clang/Utilities/includes    -std=c++11 -stdlib=libc++ -o CMakeFiles/main.dir/main.cpp.o -c /Users/chen/Code/clang/main.cpp