getNoOfObservers Function

    Function getNoOfObservers() result(no_of_observers)
      use ParamfileRegions
      implicit none
      integer                        :: no_of_observers
!
!     ---------------
!     Local variables
!     ---------------
!
      character(len=LINE_LENGTH) :: case_name, line
      integer                    :: fID
      integer                    :: io
!
!     Initialize
!     ----------
      no_of_observers = 0
!
!     Get case file name
!     ------------------
      call get_command_argument(1, case_name)

!
!     Open case file
!     --------------
      open ( newunit = fID , file = case_name , status = "old" , action = "read" )

!
!     Read the whole file to find the observers
!     ------------------------------------
readloop:do 
         read ( fID , '(A)' , iostat = io ) line

         if ( io .lt. 0 ) then
!
!           End of file
!           -----------
            line = ""
            exit readloop

         elseif ( io .gt. 0 ) then
!
!           Error
!           -----
            errorMessage(STD_OUT)
            error stop "Stopped."

         else
!
!           Succeeded
!           ---------
            line = getSquashedLine( line )

            if ( index ( line , '#defineacousticobserver' ) .gt. 0 ) then
               no_of_observers = no_of_observers + 1

            end if
            
         end if

      end do readloop
!
!     Close case file
!     ---------------
      close(fID)                             

    End Function getNoOfObservers