I'm wrapping a C++ library with cython. In the headers file, there are some structs that inherit from other structs, like so:
struct A {
int a;
};
struct B : A {
int b;
};
How should this look in my cdef extern...
block?
Using C++ in Cython doesn't mention anything special:
#file: pya.pyx
cdef extern from "a.h":
cdef cppclass A:
int a
cdef cppclass B(A):
int b
Wrapper class:
#file: pya.pyx
cdef class PyB:
cdef B* thisptr
def __cinit__(self):
self.thisptr = new B();
def __dealloc__(self):
del self.thisptr
property a:
def __get__(self): return self.thisptr.a
def __set__(self, int a): self.thisptr.a = a
property b:
def __get__(self): return self.thisptr.b
def __set__(self, int b): self.thisptr.b = b
Example:
import pyximport; pyximport.install(); # pip install cython
from pya import PyB
o = PyB()
assert o.a == 0 and o.b == 0
o.a = 1; o.b = 2
assert o.a == 1 and o.b == 2
To build it you need to instruct pyximport to use c++:
#file: pya.pyxbld
import os
from distutils.extension import Extension
dirname = os.path.dirname(__file__)
def make_ext(modname, pyxfilename):
return Extension(name=modname,
sources=[pyxfilename, "a.cpp"],
language="c++",
include_dirs=[dirname])
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