callbacks/functions pt 2?

[greg andruk]

Jr King <n at n.com> writes:

> Yesterday, I got part of my answer about passing a python function to a
> C/c++ class.  But, what was left out was passing the Python function to the
> c/c++ program, the docs did the same thing unless I skipped it.

This is covered in the 'Extended and Embedding' document, including a
code sample, in the section 'Calling Python Objects from C.'

What is mentioned in that section, but not directly shown, is that you
also need to add my_set_callback() to the method table you use with
Py_InitModule(), something like:

static PyMethodDef MyMethods[] = {
    {"set_callback",		my_set_callback,	METH_VARARGS},
    {"some_other_function",	useful_function,	METH_VARARGS},
    {NULL,			NULL}
};

To set the pointer so that C can use it, your Python script first
imports the C module, then passes the object to my_set_callback, like
so:

	def thingy(aNumber):
	   return aNumber + 1

	import my_c_module
	my_c_module.set_callback(thingy)


This relationship borders on kinky, but hey, it works.