I have c++ library that need communicate with Python plugged in modules. Communication supposes implementing by Python some callback c++ interface.

I have read already about writing extensions, but no idea how to develop inheritance.

So something about: C++:

class Broadcast
{void set(Listener *){...
}class Listener
{void notify(Broadcast* owner) = 0;
}

I need something like in Python:

class ListenerImpl(Listener):...def notify(self, owner):...

Note, I don't want use Boost.

Since I had to implement single inheritance as part of the Python C-API in a project of mine, I built a short example here. I marked the important statements in the code.

The trick is to inherit the base struct in the top of the subclass struct (leave out the PyObject_HEAD statement).

/* OBJECT */
typedef struct {MyPy_BaseClass super; // <----- PUTTING THIS FIRST INHERITS THE BASE PYTHON CLASS!!!// Own variables:// e.g int x = 0;
} MyPy_InheritanceClass;

Also dont forget to give the base type to the subclass type. There is a flag for it (see /* tp_base */).

  static PyTypeObject MyPy_InheritanceClass_Type = {PyVarObject_HEAD_INIT(NULL, 0)"MyPy_InheritanceClass",          /* tp_name */sizeof(MyPy_InheritanceClass),    /* tp_basicsize */0,                         /* tp_itemsize */(destructor)MyPy_InheritanceClass_dealloc, /* tp_dealloc */0,                         /* tp_print */0,                         /* tp_getattr */0,                         /* tp_setattr */0,                         /* tp_reserved */0,                         /* tp_repr */0,                         /* tp_as_number */0,                         /* tp_as_sequence */0,                         /* tp_as_mapping */0,                         /* tp_hash  */0,                         /* tp_call */0,                         /* tp_str */0,                         /* tp_getattro */0,                         /* tp_setattro */0,                         /* tp_as_buffer */Py_TPFLAGS_DEFAULT |Py_TPFLAGS_BASETYPE,       /* tp_flags */ "MyPy_InheritanceClass",   /* tp_doc */0,                         /* tp_traverse */0,                         /* tp_clear */0,                         /* tp_richcompare */0,                         /* tp_weaklistoffset */0,                         /* tp_iter */0,                         /* tp_iternext */MyPy_InheritanceClass_methods,    /* tp_methods */0,                         /* tp_members */0,                         /* tp_getset */&MyPy_BaseClass_Type,      /* tp_base */ // <------ GIVE THE BASE_CLASS TYPE0,                         /* tp_dict */0,                         /* tp_descr_get */0,                         /* tp_descr_set */0,                         /* tp_dictoffset */(initproc) MyPy_InheritanceClass_init, /* tp_init */0,                         /* tp_alloc */MyPy_InheritanceClass_new, /* tp_new */
};