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，并显示多个未定义的符号。

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

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

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

10.8和更早版本默认情况下选择libstdc ++，默认情况下选择10.9 libc ++。为确保与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。

相关文章：Compiling with Clang using Libc++ undefined references

修改：经过一些调查后，似乎-mmacosx-version-min与默认libstd的选择之间存在关联。如果最小版本＆lt; 10.9，然后默认libstd等于libstdc++，否则等于libc++。长期解决方案显然是使用-stdlib=libc++

Answer 2

这些建议对Mac El capitan不起作用。如果您在升级到El Capitan后遇到类似问题，请运行

xcode-select --install

在尝试编译之前

升级到Mac OS X 10.9 / Xcode 5.0.1后，C ++链接错误

2 个答案: