Important note: The source code of this example is included into SvCom package. The latest version of this example is available here: Simple NT Service Example.

As usual the first step is a Delphi project creation. SvCom components requires the NT Service Application be used as a base of project. To create it go to the Delphi's File|New dialog and select the SvCom page

Select the "NT Service Application" item from the list and press OK. The new project will be created. Save it as SvComExample1.dpr.

Note that the "uses" section of the project created does not contain Forms unit. The SvCom_NTService unit is used instead.

uses
    SvCom_NTService;

This unit contains the Application variable that is used in the same manner but performs some specific actions necessary to implement the service behaviour.

begin
    Application.Initialize;
    Application.Run;
end.

In future be aware that the Form unit is not included into the "uses" section of project file or at least the SvCom_NTService unit goes after it. Only in this case the Delphi compiler will use the Application variable from the SvCom_NTService unit, not from the Forms unit.