The main documentation of the SUM_Integer_Scalar Procedure contains additional explanation of this code listing.
function SUM_Integer_Scalar (I)
! Input variable.
type(integer), intent(in) :: I
! Output variable.
type(integer) :: SUM_Integer_Scalar
!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
! SUM_Integer_Scalar is equal to I.
SUM_Integer_Scalar = I
return
end function SUM_Integer_Scalar