链接问题Boost.Python

Question

Trying to use Boost Python, but getting linkage issues.

Code, hello.cpp:

#include <boost/python.hpp>
char const* greet() {
  return "hellow, world";
}

int main() {
  return 0;
}

BOOST_PYTHON_MODULE(hello_ext) {
using namespace boost::python;
def("greet", greet);
}

Compiling with:

g++ hello.cpp -L/usr/lib/x86_64-linux-gnu/ -I/usr/include/python3.5/ -lboost_python  /usr/lib/x86_64-linux-gnu/libpython3.5m.so -lboost_system

Getting the following linkage errors:

tmp/ccJ8ST4B.o: In function `PyInit_hello_ext':
hello.cpp:(.text+0x94): undefined reference to `boost::python::detail::init_module(PyModuleDef&, void (*)())'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyString_Size'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyUnicodeUCS4_FromEncodedObject'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyFile_FromString'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyString_Type'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyInt_Type'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyString_FromString'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyUnicodeUCS4_AsWideChar'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyString_FromStringAndSize'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `Py_InitModule4_64'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyString_FromFormat'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyNumber_Divide'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyNumber_InPlaceDivide'
/usr/lib/x86_64-linux-gnu//libboost_python.so: undefined reference to `PyInt_AsLong'

Any ideas?

Answer 1

Here while compiling give proper, exact and ordered path for libraries. Please use below command and try, If it doesn't work set LD_LIBRARY_PATH (set in program dir path only) to program directory path. This will link all the required library to your program directory.

g++  -I/usr/include/python3.5/  /usr/lib/x86_64-linux-gnu/libpython3.5m.so  -L/usr/lib/x86_64-linux-gnu/ -lboost_python -lboost_system hello.cpp -o hello

If above line do not work

export LD_LIBRARY_PATH=/program_path:$LD_LIBRARY_PATH