ctypes interface for derived C/C++ library

Question

I have two C/C++ libraries which give interface to class Solver and MultiSolver derived from Solver. I want make python API to both of them with minimum code repetition.

This means I don't want to copy/rewrite ctypes interface to function Solver when writing interface to derived MultiSolver. Currently I see 2 solutions:

• Wrap ctypes interface into python classes with hierarchy (but not very keen to do that, because it makes an other level of indirection)
• use exec command discussed here, but I think it is not very good practice
• It is very much related to question about inheritance of python modules

Here is simplified example of the problem with only few functions in the library (in reality there are many more).

C/C++ side

Solver.h

class Solver{ public:
   void solve(){ ... };   
};

MultiSolver.h

#include "Solver.h"
class MultiSolver : public Solver {  public:
   void solve_multi(){ ... };   
};

lib_commons.cpp

extern "C"{
   void solve(){ W.solve(); };
}

libSolver.cpp

#include "Solver.h"
Solver W;
#include "lib_commons.cpp"

libMultiSolver.cpp

#include "MultiSolver.h"
MultiSolver W;
#include "lib_commons.cpp"
extern "C"{
   void solve_multi(){ W.solve_multi(); };
}

Python side

libSolver.py

import ctypes 
lib = ctypes.CDLL( path+"libSolver.so" )

lib.solve.argtypes  = [] 
lib.solve.restype   = None
def solve():
    return lib.solve()

libMultiSolver.py

import ctypes 
lib = ctypes.CDLL( path+"libMultiSolver.so" )

# ========== HERE ==========
# I don't want to repeate this !!!!!
lib.solve.argtypes  = [] 
lib.solve.restype   = None
def solve():
    return lib.solve()

lib.solve_multi.argtypes  = [] 
lib.solve_multi.restype   = None
def solve_multi():
    return lib.solve_multi()