en=*), optional, intent(inout) :: comment_out
    logical, optional, intent(in) :: halt_in
end subroutine cswt_error
</PRE>
 Display error message corresponding to error_code and halt program 
 execution if required.
<P>
 Variables:
   <UL>
   <LI>  error_code:
   <LI>  [procedure]: Procedure name where s2_error called from.  Displayed 
     when error message printed to screen.
   <LI>  [comment_add]: If present, additional comment to append to default 
     error comment.
   <LI>  [comment_out]: If presen