> Yes, i have try that but seems do not work (csound output tells
> that do not recognize the first character (<) of csd.

The correct value of `narg' is 5 in your example with csd
and 6 with orc+sco.

You can see other useful examples to start in

  csound5/H/csound.h     (line 85)
  csound5/frontends/csound/csound_main.c    (line 69)

`csound_main.c' defines the csound command that we use.

tito