Errors in creating Python interface for multiple C++ files in a shared library - boost-python

Question

I have two c++ files named as "animal.cpp" and "zoo.cpp". These files are compiled as a shared library "zoo.so". I want to access the functions defined in these files from Python interpreter.
However, I am getting errors. I tried to do some changes but getting different kind of errors. I hope expert of Boost-Python may guide me in solving these issues.
Note: To keep the problem simple, I have not used classes, otherwise I could easily make classes of "animal" and "zoo".
I want to access both files function from Python.
Any guidance will be highly appreciated.
Thanks,
animal.cpp
+++++++++++
/*
* This is the C++ function we write and want to expose to Python.
*/
const std::string hello_animal() {
return std::string("hello, animal");
}
/*
* This is the C++ function we write and want to expose to Python.
*/
const std::string getname_animal() {
std::string input;
std::cout<<"Please enter your favorit animal name: ";
std::getline(std::cin,input);
return std::string("Your favorit animal name is: ").append(input);
}
/*
* This is a macro Boost.Python provides to signify a Python extension module.
*/
BOOST_PYTHON_MODULE(animal) {
// An established convention for using boost.python.
using namespace boost::python;
// Expose the function hello_animal().
def("hello_animal", hello_animal);
// Expose the function getname_animal().
def("getname_animal", getname_animal);
}
zoo.cpp
++++++++
/*
* This is the C++ function we write and want to expose to Python.
*/
const std::string hello_zoo() {
return std::string("hello, zoo");
}
/*
* This is the C++ function we write and want to expose to Python.
*/
const std::string getname_zoo() {
std::string input;
std::cout<<"Please enter your favorit zoo name: ";
std::getline(std::cin,input);
return std::string("Your favorit zoo name is: ").append(input);
}
/*
* This is a macro Boost.Python provides to signify a Python extension module.
*/
BOOST_PYTHON_MODULE(zoo) {
// An established convention for using boost.python.
using namespace boost::python;
// Expose the function hello_zoo().
def("hello_zoo", hello_zoo);
// Expose the function getname_zoo().
def("getname_zoo", getname_zoo);
}
I have created a shared library using following command:
g++ -shared -o zoo.so -fPIC zoo.cpp animal.cpp -lboost_python -lpython2.7 -I/usr/include/python2.7
Python Interpreter Commands and output:
import zoo
zoo.getname_zoo()
Please enter your favorit zoo name: zoo
'Your favorit zoo name is: zoo'
zoo.getname_animal()
Traceback (most recent call last):
File "", line 1, in
AttributeError: 'module' object has no attribute 'getname_animal'
When I make following changes in animal.cpp file, I get different error.
BOOST_PYTHON_MODULE(zoo) {
instead of
BOOST_PYTHON_MODULE(animal) {
On compilation I get following error:
[root#localhost zooexample]# g++ -shared -o zoo.so -fPIC zoo.cpp animal.cpp -lboost_python -lpython2.7 -I/usr/include/python2.7
/tmp/cci4WKrP.o: In function initzoo':
animal.cpp:(.text+0x15d): multiple definition ofinitzoo'
/tmp/cctaGDer.o:zoo.cpp:(.text+0x15d): first defined here
/tmp/cci4WKrP.o: In function init_module_zoo()':
animal.cpp:(.text+0x179): multiple definition ofinit_module_zoo()'
/tmp/cctaGDer.o:zoo.cpp:(.text+0x179): first defined here
collect2: error: ld returned 1 exit status
+++++++++++++++++++++++++++++UPDATED++++UPDATED+++++UPDATED+++++++++++++++
Considering the suggestion given by Dan for my previous issue. Now I have created a separate file pyintf.cpp containing the following code:
BOOST_PYTHON_MODULE(pyintf) {
def("hello_zoo", hello_zoo);
def("getname_zoo", getname_zoo);
def("hello_animal", hello_animal);
def("getname_animal", getname_animal);
}
but when I compile and create a shared library using the following command:
g++ -shared -o pyintf.so -fPIC pyintf.cpp -lboost_python -lpython2.7 -I/usr/include/python2.7
I get following error when I import the "pyintf" module in python.
import pyintf
Traceback (most recent call last):
File "", line 1, in
ImportError: ./pyintf.so: undefined symbol: _Z9hello_zoov
Can anyone tell what I am not doing correctly?
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Answer 1

The issues were resolved by putting all methods which I wanted to expose in a single pyintf.cpp. The errors which I got after update were due to missing header files and source files.
Now, the above issue has resolved by adding header files (zoo.h, animal.h) and source files (zoo.cpp, animal.cpp) in the compilation command. g++ -shared -o pyintf.so -fPIC pyintf.cpp animal.h animal.cpp zoo.h zoo.cpp -lboost_python -lpython2.7 -I/usr/include/python2.7
Thanks Dan for corrections.