【列表5.25】程序frmRunAt.pas的原代碼片段。
{
   frmRunAt  -Demonstration of scheduling a task for running once at a later time 
}
unit frmRunAt;
{…}
function TrunAtManinForm.CreateCommandline(var Cmd:Srting;var Parms:String):Boolean;
begin
   Cmd:=’ ‘;
   Parms:=’ ‘;
   Result:=False;
{ Do the hours}
if (StrToInt(HoursEdit.,.x,) > 0) and (StrToInt(HoursEdit.Text) <13)
   then Cmd := HoursEdit. Text+ ':'
   else begin
            ErrorMessage('Improper hours value');
            Exit;
          end;
  { Do the minutes }
  if (StrTotnt(MinsEdit.Text) >= 0) and (StrToInt(MinsEdit.Text) < 60)
   then Cmd := Cmd + MinsEdit.Text
   else begin
            ErrorMessage('Improper minutes value');
            Exit;
          end;
  { Do AM/PM }
  if AMRB.Checked
   then Cmd := Cmd + 'am '
   else Cmd := Cmd + 'pm ';
  [ Do Day/Month }
  if not TodayRB.Checked
   then begin
            Cmd := Cmd + HonthCombo. Items[MonthCombo. ItemIndex];
            Cmd := Cmd + ' ' + IntToStr(DayCombo. ItemIndex + 1) + ' ';
            end;
  if FileRB.Checked
   then begin { pass everything on command line }
     if (Length(FileNameEdit.Text) > 0) and
               (FileExists(FileNameEdit.Text))
            then begin
                     Cmd := Cmd + '< ' + FileNameEdit. Text;
                    end
            else begin
                      ErrorMessage('Specified file doesn''t exist');
                      Exit;
                    end;
          end
  else begin { pass manual parameters separately }
           Parms := TextEdit.Text;
          end;
 Result := True;
end;

procedure TRunAtMainForm. WriteSchedule;
const
  READ_IOMode : ='r'; { read mode from pipe }
  WRITE_IOMODE := 'w'; { write mode from pipe }
var
  Command : array[0..128] of char;
  CmdLineArr : array[0..512] of char;
  CmdLine : String;
  ParamArr : array[0..512] of char;
  Params : String;
  F : PIOFile;
  ErrNum : Integer:
begin
  CmdLine := '':
  Params  :=  '';
  if CreateCommandline(CmdLine, Params)
   then begin
             if FileRB.Checked
              then begin { pass the file name on the command line }
                  errormessage(CmdLine);
                       StrCopy(Command, 'at ');
                       StrPCopy(CmdLineArr, CmdLine);
                       StrCat(Command,CmdLineArr);
                       F := popen(Command, READ_IOMode);
                       ErrNum := pclose(F),
                       if ErrNum <> -1
                         then MessageDlg('Success', 'Your event has been '
                                 +'scheduled', mttnformation, [mbOK], 0)
                   else ErrorMessage('Error encountered while trying to '
                               + 'close pipe to "at" utility');
                    end
            else begin { Send the params via stdin }
                     StrCopy(Command, 'at ');
                     StrPCopy(CmdLineArr, CmdLine);
                     StrCat(Command, CmdLineArr);
                     StrPCopy(ParamArr, Params);
                     F := popen(Command, WRITE_IOMode);
                     fputs(ParamArr. F);  { write the params line }
                     fputc(ord(LF), F);   { write the newline }
                     fputc(ord(EOT), F);   { write the EOT }
                     ErrNum := pclose(F);
                     if ErrNum <> -1
                     then MessageDlg('Success', 'Your event has been '
                                +'scheduled', mtInformation, [mbOK], 0)
                    else ErrorMessage('Error encountered while trying to '
                                + 'close pipe to "at" utility');
                    end;
          end
  else ErrorMessage('Unable to schedule the event');
end;