I'm not an expert, but I can quote the tutorial.
 Here is their code for a unit -> window bound function.

value curses_initscr(value unit)
{
  CAMLparam1 (unit);
  CAMLreturn ((value) initscr()); 
}

 That's why I use CAMLprim f (value unit) { CAMLreturn(Val_unit) }

--
        David Baelde
	Etudiant en Info à l'ENS Lyon
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