Embedding Python - How to create a class instance

[Denis S. Otkidach]

On Sun, 19 Jun 2005 10:29:53 +0300
Miki Tebeka <miki.tebeka at zoran.com> wrote:

> I'm trying to embed Python in a C application.
> What I didn't find is how to create an instance once I have a class object.

Class is a callable object.  Just call it to create instance.

> I'd like to do the equivalent of:
> 
>     from a import A
>     obj = A()
>     obj.foo(10)
> 
> The following code omits error checking for clarity.
> --- a.py ---
> class A:
>     def foo(self, x):
>         print "A got %d" % x
> --- a.py ---
> 
> --- a.c ---
> int
> main()
> {
>     PyObject *module, *A, *dict, *a, *args;
>     PyObject *obj;
> 
>     Py_Initialize();
> 
>     PyRun_SimpleString("import sys; sys.path.append('.')");
> 
>     module = PyImport_ImportModule("a");
>     dict = PyModule_GetDict(module);
>     A = PyDict_GetItemString(dict, "A");
>     /* FIXME: Create obj as instance of A (a = A()) */
>     obj = ???

obj = PyObject_CallObject(A, NULL);

> 
>     foo = PyObject_GetAttrString(obj, "foo");
>     args = Py_BuildValue("(O, i)", obj, 49);
>     PyObject_CallObject(foo, args);

PyObject_CallMethod(obj, "foo", "i", 49);

>     Py_Finalize();
> 
>     return 0;
> }
> --- a.c ---

-- 
Denis S. Otkidach
http://www.python.ru/      [ru]