anchor.diff:  
         interface
            function plrandd()
  +            use plplot_flt
  +            real (kind=plflt) :: plrandd
            end function plrandd
         end interface
   
         interface
            function plrandi()
  +            integer :: plrandi
            end function plrandi
         end interface
   
  
positive.code:       end interface
  
        interface
           subroutine plseed()
           end subroutine plseed
        end interface
  
  
negative.code:       end subroutine plfill3
  
        subroutine plgriddata( x, y, z, xg, yg, zg, type, data )
           real(kind=plflt), dimension(:)   :: x, y, z, xg, yg
           real(kind=plflt), dimension(:,:) :: zg
           real(kind=plflt)                 :: data
           integer                          :: type
  
           call plgriddataf77( x, y, z, size(x), xg, size(xg), yg, size(yg), zg, &
  