Re: [pygame] Midi Crashes on Error

[Lenard Lindstrom <len-l@xxxxxxxxx>]

On 13-11-03 09:57 AM, Christopher Arndt wrote:
> Hi Lenard,
>
> On 02.11.2013 02:25, Lenard Lindstrom wrote:
> > Just wondering, if the Python level callback is found to be too slow, could a
> > C level callback mechanism be provided?
> how would you suggest this should be used? From Python or C?
>
> In python-rtmidi this is currently not possible from Python, because
> 'MidiIn.set_callback' wraps a Python callback function with a C function
> implemented in Cython (and you can't access the C++ object directly in
> Python, only in the Cython code).
>
> I guess it would be easy to make the C++ method 'RtMidiIn.setCallback'
> available directly in Python, but I'm not sure how a pointer to a C
> function could be passed by Python then or how such a pointer could be
> obtained by Python.
>
> So any ideas about a suitable API for this? And how it would tie into
> PyGame's C code?
>
>
> Chris
Cython has a C level sharing mechanism with cimport:

http://docs.cython.org/src/userguide/sharing_declarations.html#sharing-declarations-between-cython-modules

This should be usable from a standard C extension module. So something like:

int RtMidi_SetCallback(PyObject *midi_in, RtMidiCallback callback, void 
*data);

Anyway, I don't see any rush in implementing this. It may be that using 
a Python callback will be fast enough.

Lenard