uses
Forms,
Windows,
Unit1 in 'Unit1.pas' {Form1};
{$R *.res}
var
hMutex:hWnd;
begin
Application.Initialize;
Application.Title:='test';
hMutex:=CreateMutex(nil,false,'test');
if GetLastError<>Error_Already_Exists then
begin
Application.CreateForm(TForm1, Form1);
Application.Run;
end
else
begin
Application.MessageBox('本程序只允许同时运行一个','Error');
ReleaseMutex(hMutex);
end;
end.