Como criar um serviço (Service applications) usando Delphi

program ACServico;

uses
  SvcMgr,
  ACServicoUnit in 'ACServicoUnit.pas' {ac_servico_update: TService};

{$R *.RES}

begin
  // Windows 2003 Server requires StartServiceCtrlDispatcher to be
  // called before CoRegisterClassObject, which can be called indirectly
  // by Application.Initialize. TServiceApplication.DelayInitialize allows
  // Application.Initialize to be called from TService.Main (after
  // StartServiceCtrlDispatcher has been called).
  //
  // Delayed initialization of the Application object may affect
  // events which then occur prior to initialization, such as
  // TService.OnCreate. It is only recommended if the ServiceApplication
  // registers a class object with OLE and is intended for use with
  // Windows 2003 Server.
  //
  // Application.DelayInitialize := True;
  //
  if not Application.DelayInitialize or Application.Installing then
    Application.Initialize;
  Application.CreateForm(Tac_servico_update, ac_servico_update);
  Application.Run;
end.

 
unit ACServicoUnit;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, SvcMgr, Dialogs;

type
  Tac_servico_update = class(TService)
  private
    { Private declarations }
  public
    function GetServiceController: TServiceController; override;
    { Public declarations }
  end;

var
  ac_servico_update: Tac_servico_update;

implementation

{$R *.DFM}

procedure ServiceController(CtrlCode: DWord); stdcall;
begin
  ac_servico_update.Controller(CtrlCode);
end;

function Tac_servico_update.GetServiceController: TServiceController;
begin
  Result := ServiceController;
end;

end.