升级到 Mac OS X 10.9 / Xcode 5.0.1 后出现 C++ 链接错误

Question

升级到 Mac OS X 10.9 / Xcode 5.0.1 后，创建共享库 (.dylib) 的命令行失败，出现多个未定义符号。

clang++ -dynamiclib -install_name test.dylib *.o -o test.dylib
Undefined symbols for architecture x86_64:
  "std::allocator<char>::allocator()", referenced from:
      _main in test.o
  "std::allocator<char>::~allocator()", referenced from:
      _main in test.o
  "std::ostream::operator<<(std::ostream& (*)(std::ostream&))", referenced from:
      _main in test.o
  "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)", referenced from:
      _main in test.o
  "std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()", referenced from:
      _main in test.o
  "std::ios_base::Init::Init()", referenced from:
      ___cxx_global_var_init in test.o
  "std::ios_base::Init::~Init()", referenced from:
      ___cxx_global_var_init in test.o
  "std::cout", referenced from:
      _main in test.o
  "std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)", referenced from:
      _main in test.o
  "std::basic_ostream<char, std::char_traits<char> >& std::operator<<<char, std::char_traits<char>, std::allocator<char> >(std::basic_ostream<char, std::char_traits<char> >&, std::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)", referenced from:
      _main in test.o
ld: symbol(s) not found for architecture x86_64

Answer 1

答案就在那里：https://mathematica.stackexchange.com/questions/34692/mathlink-linking-error-after-os-x-10-9-mavericks-upgrade

在 OS X 上有两种可用的标准 C++ 库实现：libstdc++ 和 libc++。它们不是二进制兼容的，libMLi3 需要 libstdc++。

在 10.8 和更早版本上默认选择 libstdc++，在 10.9 上默认选择 libc++。为了保证与 libMLi3 的兼容性，我们需要手动选择 libstdc++。

为此，请将 -stdlib=libstdc++ 添加到链接命令中。

相关帖子：Compiling with Clang using Libc++ undefined references

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编辑：经过一些调查，-mmacosx-version-min 和默认libstd 的选择之间似乎存在联系。如果最低版本 libstd 等于 libstdc++，否则为 libc++。长期的解决方案显然是使用-stdlib=libc++

Answer 2

这些建议对我来说不适用于 Mac El capitan。如果您在升级到 El Capitan 后遇到类似问题，只需运行

xcode-select --install

在尝试编译之前