Hi ! I’m trying to write my first external, and have studied the externals-howto. I understand, for example how the pan~ example works (I think, I'm a noob in C), but in my case I'm confused:

I want to implement a recursive algorithm, I need to copy the inlet vector into an array A perform some operations, copy the restult in array B, swap arrays, and start over again several times until I can finaly copy one of the arrays into the outlet vector.

How do I have to treat these arrays in the code? should they be of type t_sample?
In the perform section should I treat them as the inlets and outlets?

t_int *foo_perform(t_int *w)
{
  t_sample  *in =    (t_sample *)(w[1]);
  t_sample  *out =    (t_sample *)(w[2]);
  t_sample  *a =    (t_sample *)(w[3]);
  t_sample  *b =    (t_sample *)(w[4]);
  int          n =           (int)(w[5]);

@allister How did you set it up in your *_dsp method? Are the arrays t_garray, t_array, array of t_sample, something else... ?

Also keep in mind that the API will happily use the same memory location for both the input and output vectors.

1. Add a t_sample (IMHO double is preferable) pointer in the struct of your object.
2. Allocate (and/or release previous) memory (according to the vector size) in the dsp method.
3. Pass a pointer to your struct object in the dsp_add call.
4. Fetch it in dsp_perform ; "TADA !"
5. Don't forget to release memory (if any) in the free method of your object.
6. Send me an email if your are in Montpellier

@jancsika, it would be t_sample, but I had to pause my little expriments. Thanks guys, I hope to be back at it in two weeks and nail this thing or come back with better questions.
@Nicolas-Danet you're in Montpellier, awesome! I will contact you soon I'd love to talk to someone who knows this stuff, it can be hard to learn on your own.

I learned everything alone ; i know how hard it can be! We could create a Pure Data group in Montpellier.