C with a SPIN object - example - PropWare_Spin2Dat

Hi David Zemon, I hope you can help me.

I was thinking how is the best way to use a SPIN object from a C program. After see some examples of PropWare I understand that I need some help to understand!!

I think that "PropWare_Spin2Dat" is a good example for some questions.

1 - I can use any SPIN object in C?
2 - In the example PropWare_Spin2Dat how you call the "pst.spin"? But if is

#include <fdserial.h>

why you include "pst.spin" too? This is probably a no sense question, but I need to ask because I don´t understand how this work.
3 - You have more examples with other SPIN objects?

Thanks