Compiling boost::program_options on Mac OS X with g++ 4.8 (Mac Ports)

Question

I'm trying to compile one of the boost::program_options examples, http://svn.boost.org/svn/boost/trunk/libs/program_options/example/first.cpp, using gcc 4.8 (installed via MacPorts). However, I keep getting errors:

Undefined symbols for architecture x86_64:
  "boost::program_options::to_internal(std::basic_string, std::allocator > const&)", referenced from:
      std::vector, std::allocator >, std::allocator, std::allocator > > > boost::program_options::to_internal, std::allocator > >(std::vector, std::allocator >, std::allocator, std::allocator > > > const&) in ccEWnIGV.o
  "boost::program_options::options_description::options_description(std::basic_string, std::allocator > const&, unsigned int, unsigned int)", referenced from:
      _main in ccEWnIGV.o
  "boost::program_options::invalid_option_value::invalid_option_value(std::basic_string, std::allocator > const&)", referenced from:
      void boost::program_options::validate(boost::any&, std::vector, std::allocator >, std::allocator, std::allocator > > > const&, double*, long) in ccEWnIGV.o
  "boost::program_options::error_with_option_name::error_with_option_name(std::basic_string, std::allocator > const&, std::basic_string, std::allocator > const&, std::basic_string, std::allocator > const&, int)", referenced from:
      boost::program_options::validation_error::validation_error(boost::program_options::validation_error::kind_t, std::basic_string, std::allocator > const&, std::basic_string, std::allocator > const&, int) in ccEWnIGV.o
  "boost::program_options::detail::cmdline::set_additional_parser(boost::function1, std::allocator >, std::basic_string, std::allocator > >, std::basic_string, std::allocator > const&>)", referenced from:
      boost::program_options::basic_command_line_parser::extra_parser(boost::function1, std::allocator >, std::basic_string, std::allocator > >, std::basic_string, std::allocator > const&>) in ccEWnIGV.o
  "boost::program_options::detail::cmdline::cmdline(std::vector, std::allocator >, std::allocator, std::allocator > > > const&)", referenced from:
      boost::program_options::basic_command_line_parser::basic_command_line_parser(int, char const* const*) in ccEWnIGV.o
  "boost::program_options::operator >&, boost::program_options::options_description const&)", referenced from:
      _main in ccEWnIGV.o
  "boost::program_options::abstract_variables_map::operator[](std::basic_string, std::allocator > const&) const", referenced from:
      boost::program_options::variables_map::operator[](std::basic_string, std::allocator > const&) const in ccEWnIGV.o
  "boost::program_options::error_with_option_name::substitute_placeholders(std::basic_string, std::allocator > const&) const", referenced from:
      vtable for boost::program_options::invalid_option_value in ccEWnIGV.o
      vtable for boost::program_options::validation_error in ccEWnIGV.o
etc...

The boost libraries were installed via MacPorts, placing the header files in /opt/local/include and library files in /opt/local/lib. The compile command used was:

$ g++ -I/opt/local/include first.cpp -L/opt/local/lib -lboost_program_options-mt

Compiling header-only boost functions work fine using g++ 4.8 i.e factorial, hermite etc.

What I find strange is that this example compiles if I use the llvm-g++ compiler:

$ llvm-g++ -I/opt/local/include first.cpp -L/opt/local/lib -lboost_program_options-mt

 $ g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/opt/local/libexec/gcc/x86_64-apple-darwin12/4.8.1/lto-wrapper
Target: x86_64-apple-darwin12
Thread model: posix
gcc version 4.8.1 (MacPorts gcc48 4.8.1_3)

\

 $ llvm-g++ -v
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.0
Thread model: posix

\

Why doesn't this example compile with gcc 4.8? Any ideas? Is there a way to fix this?

Update: The example also compiles using clang++

Sepalous

Answer 1

As Shigerello already mentioned, the problem lies in boost compiled with clang and boost compiled with gcc being incompatible.

A simpler variation to get boost compiled with GCC-4.8 is to just use the gcc48 variant of boost:

sudo port install boost +gcc48

Topmast

Hi agi, this worked flawlessly without problems! Though Shigerello gave an excellent explanation, the simplicity of your solution cannot go unnoticed. This method did not give problems with conflicting gmp files. – Sepalous

Answer 2

I suspect you're using Boost compiled with Clang, which is incompatible with GCC.

This is because C++ implementation differs between them, and Clang's STL classes are put in a namespace different from GCC's using inline namespace for the sake differentiating Clang from more popular GCC; e.g. std::basic_string is std::__1::basic_string in Clang by inline namespace).

Try a command below, If you see "libc++" in output, yes, your Boost was built with Clang (or "libstdc++" for GCC):

$ otool -L /opt/local/lib/libboost_program_options-mt.dylib
/opt/local/lib/libboost_program_options-mt.dylib:
    /opt/local/lib/libboost_program_options-mt.dylib (compatibility version 0.0.0, current version 0.0.0)
    /usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 120.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1213.0.0)

If Boost was built with Clang, I recommend you to rebuild Boost with GCC-4.8 provided by MacPorts:

sudo port upgrade --force boost configure.compiler=macports-gcc-4.8

You can find other available compilers in https://trac.macports.org/wiki/UsingTheRightCompiler#configure-compiler .


Other useful link: http://wiki.inkscape.org/wiki/index.php/CompilingMacOsX#Compiling_with_clang_3.3_and_libc.2B.2B_.28c.2B.2B11_enabled.29_.282013.29

Th

Thank you so much for that excellent answer! As you suspected, I did see "libc++" when I ran the otool command, however using your command to rebuild boost using gcc4.8 failed on my machine - more an issue of conflicting gmp files, which I will have to sort out. I skipped the rebuilding of dependences using sudo port -ns upgrade --force boost configure.compiler=macports-gcc-4.8 which worked. The boost example compiled and ran perfectly. Cheers. – Sepalous