I want to export a python class to be used in C++:
class Object:
def method(self):
pass
cdef public object create_object() with gil:
return Object()
cdef public void py_method(object obj) with gil:
obj.method() # obj is expected to have method()
Then the generated header file will have the following functions:
__PYX_EXTERN_C PyObject *create_object(void);
__PYX_EXTERN_C void py_method(PyObject *);
My question is: should I also have a function like
from cpython cimport Py_XDECREF, PyObject
cdef public void destroy_object(PyObject* obj) with gil:
Py_XDECREF(obj)
to avoid memory leak?
Then these functions may be used in C++ code like:
auto obj = create_object()
py_method(obj)
// Finally
destroy_object(obj)
Yes you should decrement it when calling it from C++. You could do it the way you propose or you could skip the definition of destroy_object and just use Py_XDECREF in C++.
Other things you should consider:
create_object can return NULL if it's raised a Python exception so check for that