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// SWIG Module for handling some callback functions written in Python
%module callback
%{
#include "widget.h"
%}
/* These are some normal C functions for our "widget." */
/* Note : use of a typedef for function pointers is required */
typedef double (*CALLBACK)(double, void *);
Widget *new_widget();
double widget_op(Widget *w, double a);
void widget_add_callback(Widget *w, CALLBACK callback, void *);
// ----------------------------------------------------------------
// Python helper functions for adding callbacks
// ----------------------------------------------------------------
%{
/* This function matches the prototype of a normal C callback
function for our widget. However, the clientdata pointer
actually refers to a Python callable object. */
static double PythonCallBack(double a, void *clientdata)
{
PyObject *func, *arglist;
PyObject *result;
double dres = 0;
func = (PyObject *) clientdata;
arglist = Py_BuildValue("(d)",a);
result = PyEval_CallObject(func,arglist);
Py_DECREF(arglist);
if (result) {
dres = PyFloat_AsDouble(result);
}
Py_XDECREF(result);
return dres;
}
/* This function adds a new Python function object as a callback object */
static void pywidget_add_callback(Widget *w, PyObject *PyFunc) {
widget_add_callback(w,PythonCallBack, (void *) PyFunc);
Py_INCREF(PyFunc);
}
%}
// -------------------------------------------------------------------
// SWIG typemap allowing us to grab a Python callable object
// -------------------------------------------------------------------
%typemap(python,in) PyObject *PyFunc {
if (!PyCallable_Check($source)) {
PyErr_SetString(PyExc_TypeError, "Need a callable object!");
return NULL;
}
$target = $source;
}
// Our new python callback registration function. Note the use of
// a typemap to grab a PyObject.
void pywidget_add_callback(Widget *w, PyObject *PyFunc);
// Now make a symbol for our C callback function
%{
/* Need to declare it in our file */
extern double foo(double, void *);
%}
// Create a constant 'FOO' that is the address of a C callback function
const CALLBACK FOO = foo;
// C function for filling an array
extern void fill_array(Widget *w, double *data, int nitems);
// Grab SWIG array module
%include array.i
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