Bind and Listen on an Available Port in a Range

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Demonstrates Socket.BindAndListenPortRange, which searches an inclusive port range for an available TCP port, binds it, and begins listening. It returns the selected port, or -1 on failure.

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.Socket;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  socket: TSocket;
  boundPort: Integer;

begin
  socket := TSocket.Create;

  //  Search the inclusive port range for an available TCP port, bind it, and begin listening.  The
  //  method returns the selected port, or -1 when no port can be bound.
  boundPort := socket.BindAndListenPortRange(5000,5100,25);
  if (boundPort < 0) then
    begin
      WriteLn(socket.LastErrorText);
      Exit;
    end;
  WriteLn('Listening on port ' + boundPort);


  socket.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.