[pygtk] gtk threads with a C extension module and callback

[Kim Novak]

Thanks! Your solution worked.
Kim

Gustavo J. A. M. Carneiro wrote:
> On Wed, 2006-02-01 at 10:19 -0600, Kim Novak wrote:
>   
>> I am having an issue when I enable gtk threading (call 
>> gtk.threads_init() then gtk.main()). I'm not actually running any other 
>> threads yet but would like to, thus I have to call gtk.threads_init(). I 
>> don't know if this is a pygtk, gtk, python issue or user ignorance.
>>
>> I've narrowed this down to a small example. The python code registers a 
>> callback with the C extension module then calls gtk.main. The C 
>> extension module registers a glib timeout event. When the timeout occurs 
>> the C code invokes the Python callback. It works if I don't call 
>> gtk.threads_init() and seg faults if I do.
>>
>>     
>
>
>   Check my pseudo-diff to your python callback wrapper for the fix:
>
>
>   
>> /* The timeout event handler for gtk event loop */
>> gint
>> on_timeout(gpointer data)
>> {
>>        PyObject *arglist;
>>        PyObject *result;
>>     
> +    PyGILState_STATE state;
> +
> +    state = pyg_gil_state_ensure();
>
>   
>>        /* Time to call the callback */
>>        arglist = Py_BuildValue("(i)", ++counter);
>>        result = PyEval_CallObject(my_callback, arglist);
>>        Py_DECREF(arglist);
>>     
>
> +    if (!result)
> +	PyErr_Print();
> -    Py_DECREF(result);
> +    Py_XDECREF(result);
> +    pyg_gil_state_release(state);
>
>   
>>        return 1;
>> }
>>
>>     
>
>