! This file: http://ftp.aset.psu.edu/pub/ger/fortran/hdk/KindExample.f90
!
! Illustrates how to program a Real Kind option.
!
! Authors: "Michael Metcalf" <michaelmetcalf@compuserve.com>
! in answer to question posed by:
! "Stig Kildegård Andersen" <stig@dontspam.tk.k-net.dk>
!
! Date: 11 December 2001.
!
module kind_module
  implicit none
  integer, parameter :: rk = kind(1.d0)

contains

  function func(x) result(y)

  implicit none
  real(rk), intent(in) :: x
  real(rk) :: y
  y = x
  end function

end module

  program test
  use kind_module
  implicit none

  real(rk) :: x
  x = 5.0_rk
  write (*,*) x
  x= 2.0_rk*func(x)
  write (*,*) x
  write (*,*) 'Press Enter to end this example.'
  read(*, "()")

  end program test