Error building Python extension using boost.python - c++

Question

I installed boost as well as boost-python, and boost-build using homebrew on my Mac with OS X 10.11.6. I am running Python 3.5.2. boost is set up correctly and works in C++ projects. Both, user-config.jam and the jamfile located in my python extension project directory are ok. I tried to compile a shared library from the following source
#include <iostream>
#include <boost/python.hpp>
using namespace std;
void say_hello() {
std::cout << "HELLO!!!!!";
}
BOOST_PYTHON_MODULE(hello) {
using namespace boost::python;
def ("say_hello", say_hello);
}
using the b2 interpreter. It issues the following command:
"g++" -dynamiclib -Wl,-single_module -install_name "hello.so" -L"/usr/local/lib/python3.5" -o "bin/darwin-4.2.1/release/hello.so" "bin/darwin-4.2.1/release/say_hello.o" -lpython3.5 -headerpad_max_install_names -Wl,-dead_strip -no_dead_strip_inits_and_terms
, which crash with
darwin.link.dll bin/darwin-4.2.1/release/hello.so
Undefined symbols for architecture x86_64:
"typeinfo for boost::python::objects::py_function_impl_base", referenced from:
[...long trace back ...]
"boost::python::detail::init_module(PyModuleDef&, void (*)())", referenced from:
_PyInit_hello in say_hello.o ld: symbol(s) not found for architecture x86_64
I am very aware of all the question concerning similar problems, but unfortunately none of them provides a working answer.
What do I have to do I order to get this simple code working as an Python extension module?

Answer 1

You should link it with boost python library as well( as boost.python is not header only). Here is how boost libraries are include in the build command(paths as I have on my machine):
-L/usr/lib/libpython2.7.dylib /usr/local/lib/libboost_system-mt.dylib /usr/local/lib/libboost_python-mt.dylib /usr/lib/libpython2.7.dylib -Wl,-rpath,/usr/lib/libpython2.7.dylib
I assume you can do without libboost_system library. (Such output I get when run make VERBOSE=1 as I'm not running make explicitly.)
Regarding cmake, here is a simple CMakeLists.txt you can use to build a project with Boost.Python:
cmake_minimum_required(VERSION 2.8)
set(LIBRARY_NAME "ext") # ext for extension
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -ggdb")
set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/build)
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/lib)
set(SOURCES
python_interface.cpp
main.cpp
)
set(CMAKE_MACOSX_RPATH ON)
# Get Boost
find_package(Boost COMPONENTS
system
python REQUIRED)
include_directories(${Boost_INCLUDE_DIRS})
link_directories(${Boost_LIBRARY_DIRS})
# Get Python
find_package(PythonLibs REQUIRED)
include_directories(${PYTHON_INCLUDE_DIRS})
link_directories(${PYTHON_LIBRARIES})
add_library(${LIBRARY_NAME} SHARED ${SOURCES})
target_link_libraries(${LIBRARY_NAME}
${Boost_LIBRARIES}
${PYTHON_LIBRARIES}
)