Delphi - call next_permutation

program Project_d_permut;
{$APPTYPE CONSOLE}

uses
  System.SysUtils,
  System.Diagnostics,
  Next_perm_string in 'Next_perm_string.pas';

var
    s          : AnsiString;
    i, len     : integer;
    StopWatch  : TStopwatch;

begin
    s    := 'abcdef';  //ghijkl';
    len  := length(s)+1;
    i    := 0;

    StopWatch := StopWatch.StartNew;

    repeat  begin
        if (i<6)  then writeln( s );           //comment out for performance
        inc(i);
    end
    until not  D_next_permutation(s, 1, len ) ;

    StopWatch.Stop;
    writeln;
    writeln( 'Delphi  ', i );
    writeln( 'Seconds: ',  StopWatch.elapsedMilliSeconds/1000:2:3 );

    readln;
end.