Fortran Wiki
proc_component_example

This example was posted to comp.lang.fortran by “Simulate” on December 12, 2008.

module proc_component_example

    type t
        real :: a
        procedure(print_int), pointer, nopass :: proc
    end type t

    abstract interface

    subroutine print_int (arg, lun)
        import
        type(t), intent(in) :: arg
        integer, intent(in) :: lun
    end subroutine print_int

    end interface

contains

    subroutine print_me (arg, lun)
        type(t), intent(in) :: arg
        integer, intent(in) :: lun
        write (lun,*) arg%a
    end subroutine print_me

    subroutine print_my_square (arg, lun)
        type(t), intent(in) :: arg
        integer, intent(in) :: lun
        write (lun,*) arg%a**2
    end subroutine print_my_square

end module proc_component_example

program main

    use proc_component_example
    use iso_fortran_env, only : output_unit

    type(t) :: x

    x%a = 2.71828

    x%proc => print_me
    call x%proc(x, output_unit)
    x%proc => print_my_square
    call x%proc(x, output_unit)

end program main