The main documentation of the COUNT_Scalar Procedure contains additional explanation of this code listing.
function COUNT_Scalar (L) ! Input variable. type(logical), intent(in) :: L ! Output variable. type(integer) :: COUNT_Scalar !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ! COUNT_Scalar is equal to the number of trues in L, ! so it is 1 if L is true, 0 if L is false. if (L) then COUNT_Scalar = 1 else COUNT_Scalar = 0 end if return end function COUNT_Scalar