anchor.diff:          call write_column_title(iunit, '# states', int_val=.true., justify=1)
           call write_column_title(iunit, '# spawn_events', int_val=.true., justify=1)
           if (present(nattempts)) then
  -            if (nattempts) call write_column_title(iunit, '# attempts', int_val=.true., justify=1)
  +            if (nattempts) call write_column_title(iunit, '# attempts', int_64_val=.true., justify=1)
           end if
           call write_column_title(iunit, 'R_spawn', low_prec_val=.true.)
           call write_column_title(iunit, '  time', low_prec_val=.true., justify=2)
  
positive.code: 
          sep_loc = ' '
          if (present(sep)) sep_loc = sep
          write (io, '(i24,a1,1X)', advance='no') val, sep_loc
  
      end subroutine write_qmc_var_int_64
  
  
negative.code: 
      end subroutine write_dmqmc_report_header
  
      subroutine write_column_title(io, key, int_val, int_64_val, low_prec_val, justify, sep)
  
          ! Write column headers using the same column width as write_qmc_var.
  
  