The main documentation of the Set_Version_Distributed_Vector Procedure contains additional explanation of this code listing.
subroutine Set_Version_Distributed_Vector (DV, Version) ! Input variable. type(integer), intent(in) :: Version ! Version number. ! Input/Output variable. type(Distributed_Vector_type), intent(inout) :: DV ! Variable to be set. !~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ! Verify requirements. VERIFY(Valid_State(DV),5) ! DV is valid. ! Set the value. DV%Version = Version ! Verify guarantees - none. return end subroutine Set_Version_Distributed_Vector