unit UnitOpenEvent;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    EventHandle: Thandle;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  {open the previously existing event}
  EventHandle := OpenEvent(EVENT_ALL_ACCESS, FALSE, 'MyEvent');
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  {set the event, which was opened from the other application}
  SetEvent(EventHandle);
end;

end.