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Am trying to build the example inspired from here

My original intention is to be able to call C++ code from within Python. I'm just running the examples from the Boost documentation in order to achieve this goal.

Here's my makefile

CXX               := g++
CXX_FLAGS         := -Wall -Wextra -std=c++17 -ggdb

BIN               := bin
SRC               := src
INCLUDE           := inc
LIB               := lib

BOOST_ROOT        := /home/eicossa/repo/boost_install
BOOST_INCL        := ${BOOST_ROOT}/include/
BOOST_LIBS        := ${BOOST_ROOT}/libs/ 

PYTHON_INCL       := /usr/include/python3.7m/
PYTHON_LIBS       := /usr/lib/python3.7/

LIBFLAGS          := -lboost_system 
EXECUTABLE        := greet


all: $(BIN)/$(EXECUTABLE)

run: clean all
        clear
        ./$(BIN)/$(EXECUTABLE)

$(BIN)/$(EXECUTABLE): $(SRC)/*.cpp 
        $(CXX) $(CXX_FLAGS) -I$(PYTHON_INCL) -I$(INCLUDE) -I$(BOOST_INCL) -L$(BOOST_LIBS) -L$(PYTHON_LIBS) -L$(LIB$

clean:
        -rm $(BIN)/*

This leads to the following errors

/tmp/ccNVjFX3.o: In function boost::python::api::object::object()': /home/eicossa/repo/boost_install/include/boost/python/object_core.hpp:400: undefined reference to_Py_NoneStruct' /tmp/ccQNpbxG.o: In function PyInit_hello_ext': /home/eicossa/Dropbox/wtcd/license/boost/src/bindings.cpp:3: undefined reference toboost::python::detail::init_module(PyModuleDef&, void ()())' /tmp/ccQNpbxG.o: In function boost::python::type_info::name() const': /home/eicossa/repo/boost_install/include/boost/python/type_id.hpp:160: undefined reference toboost::python::detail::gcc_demangle(char const)' /tmp/ccQNpbxG.o: In function boost::python::to_python_value<char const* const&>::operator()(char const* const&) const': /home/eicossa/repo/boost_install/include/boost/python/converter/builtin_converters.hpp:157: undefined reference to boost::python::converter::do_return_to_python(char const*)' /tmp/ccQNpbxG.o: In function boost::python::to_python_value<char const* const&>::get_pytype() const': /home/eicossa/repo/boost_install/include/boost/python/converter/builtin_converters.hpp:157: undefined reference toPyUnicode_Type' /tmp/ccQNpbxG.o: In function void boost::python::def<char const* (*)()>(char const*, char const* (*)())': /home/eicossa/repo/boost_install/include/boost/python/def.hpp:91: undefined reference toboost::python::detail::scope_setattr_doc(char const*, boost::python::api::object const&, char const*)' /tmp/ccQNpbxG.o: In function `boost::python::api::object boost::python::detail::make_function_aux

(char const* (*)(), boost::python::default_call_policies const&, boost::mpl::vector1 const&)': /home/eicossa/repo/boost_install/include/boost/python/make_function.hpp:38: undefined reference to boost::python::objects::function_object(boost::python::objects::py_function const&)' /tmp/ccQNpbxG.o: In function boost::python::objects::py_function_impl_base::py_function_impl_base()': /home/eicossa/repo/boost_install/include/boost/python/object/py_function.hpp:20: undefined reference to vtable for boost::python::objects::py_function_impl_base' /tmp/ccQNpbxG.o:(.rodata._ZTVN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFPKcvENS0_21default_call_policiesENS_3mpl7vector1IS6_EEEEEE[_ZTVN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFPKcvENS0_21default_call_policiesENS_3mpl7vector1IS6_EEEEEE]+0x30): undefined reference to boost::python::objects::py_function_impl_base::max_arity() const' /tmp/ccQNpbxG.o: In function boost::python::objects::caller_py_function_impl<boost::python::detail::caller<char const* (*)(), boost::python::default_call_policies, boost::mpl::vector1<char const*> > >::~caller_py_function_impl()': /home/eicossa/repo/boost_install/include/boost/python/object/py_function.hpp:30: undefined reference to boost::python::objects::py_function_impl_base::~py_function_impl_base()' /tmp/ccQNpbxG.o:(.rodata._ZTIN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFPKcvENS0_21default_call_policiesENS_3mpl7vector1IS6_EEEEEE[_ZTIN5boost6python7objects23caller_py_function_implINS0_6detail6callerIPFPKcvENS0_21default_call_policiesENS_3mpl7vector1IS6_EEEEEE]+0x10): undefined reference to typeinfo for boost::python::objects::py_function_impl_base' /tmp/ccQNpbxG.o: In functionboost::python::converter::expected_pytype_for_arg::get_pytype()': /home/eicossa/repo/boost_install/include/boost/python/converter/pytype_function.hpp:69: undefined reference to boost::python::converter::registry::query(boost::python::type_info)' /home/eicossa/repo/boost_install/include/boost/python/converter/pytype_function.hpp:70: undefined reference to boost::python::converter::registration::expected_from_python_type() const' collect2: error: ld returned 1 exit status Makefile:27: recipe for target 'bin/greet' failed make: *** [bin/greet] Error 1

What am i doing wrong ?

Arjun J Rao
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  • Possible duplicate of [What is an undefined reference/unresolved external symbol error and how do I fix it?](https://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix) – ead Oct 21 '19 at 07:53

1 Answers1

1
CXX               := g++
CXX_FLAGS         := -Wall -Wextra -std=c++17 -ggdb

BIN               := bin
SRC               := src
INCLUDE           := inc
LIB               := lib

BOOST_ROOT        := /home/eicossa/repo/boost_install
BOOST_INCL        := ${BOOST_ROOT}/include/
BOOST_LIBS        := ${BOOST_ROOT}/libs/ 

PYTHON_INCL       := /usr/include/python3.7m/
PYTHON_LIBS       := /usr/lib/python3.7/

LIBFLAGS          := -lboost_system  -lboost_python37 -lpython3.7m #changes made here
EXECUTABLE        := greet


all: $(BIN)/$(EXECUTABLE)

run: clean all
        clear
        ./$(BIN)/$(EXECUTABLE)

$(BIN)/$(EXECUTABLE): $(SRC)/*.cpp 
        $(CXX) $(CXX_FLAGS) -I$(PYTHON_INCL) -I$(INCLUDE) -I$(BOOST_INCL) -L$(BOOST_LIBS) -L$(PYTHON_LIBS) -L$(LIB$

clean:
        -rm $(BIN)/*

Try out these changes in the Makefile

Arjun J Rao
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  • 1
  • 10
  • 25