[ferret_users] Embed Ferret in Fortran program

[Haoguo Hu <haoguo.hu@xxxxxxxx>]

Dear Ferret-eers,

I try to embed Ferret in Fortran program when debugging, here is an example:

!----Begin Fortran program----------------------------
        program main  !Fortran call Ferret
	integer istep
           do istep = 1,5
	     !----------
             call system("ferret -nojnl -script plot.jnl")
           enddo
        end
!----End Fortran program-------------------------------


plot.jnl
!----Begin plot.jnl------------------------------------
  use "coads_climatology"
  fill/k=1/l=1 sst
  spawn sleep 10s  !pause for viewing and changing the L=2,3,..
!----End plot.jnl--------------------------------------

I can change the "L=1,2,3,.." in plot.jnl manually.
The questions are:
1. How to make "L=istep" happen automatically?
2. How to let the Ferret window open only once and the plotting keep 
going with "istep"?


Thanks


HH