pro rd_next, fp, ln, mol, iso, v_upper, v_lower, min_nu0, max_nu0, min_s

;+
; NAME:
;  rd_next
; PURPOSE: (one line)
;  Read the next line from an open HITRAN file that satisfies criteria
; DESCRIPTION:
; CATEGORY:
;  Spectra
; CALLING SEQUENCE:
;  rd_next, fp, ln, mol, iso, v_upper, v_lower, min_nu0, max_nu0, min_s
; INPUTS:
;  ln - the spectral line structure to be filled in
;  fp - a file pointer to an open HITRAN file. 
;  mol - index of molecule (or 0 for any)
;  iso - index of isotope (or 0 for any)
;  v_upper - upper vibrational quantum number, or 0 for any
;  v_lower - lower vibrational quantum number, or 0 for any
;  min_nu0 - minimum wavenumber of the transition, or 0 for any
;  max_nu0 - maximum wavenumber of the transition, or 0 for any
;  min_s- minimum strength of the transition, or 0 for any
; OPTIONAL INPUT PARAMETERS:
;  none
; KEYWORD INPUT PARAMETERS:
;  none
; KEYWORD OUTPUT PARAMETERS:
;  none
; OUTPUTS:
;  Fills the spectral line, ln
; COMMON BLOCKS:
;  None
; SIDE EFFECTS:
; RESTRICTIONS:
;  ln must be defined before calling.
; PROCEDURE:
; MODIFICATION HISTORY:
;  Written 2000 October, by Leslie Young, SwRI
;-

  true = (1 eq 1)
  false = (1 eq 0)
  ok = false
  
  while ok eq false do begin
    rd_specline_hitran, fp, ln
    if ln.mol le 0 then return ; EOF
    ok = ok_specline(ln, mol, iso, v_upper, v_lower, min_nu0, max_nu0, min_s)
  end
  return

end