In Delphi (2007) ShareMem must be declared as the first item in the uses of the unit you are using and also in your application file.  Then declare:

function WebUpdate(strPath: string): Integer; stdcall external'wuw4.dll';

Then call the exported WebUpdate() function with:

procedure CheckForUpdatesExecute();var strPath: string;
    intResult: integer;begin 
    strPath := 'https://mycompany.com/myscript.txt' 
    intResult := WebUpdate(strPath);if intResult = 0 then 
        ShowMessage('Unable to check for updates because the update components are not installed.');end; 

That's it!  You are ready to move on to the next step - authoring your update script.

Alternatively, install the supplied wuwstub.exe utilty into the same folder as your application and launch it as a child process, passing the URL of your update script as a command line argument.  (Note: this method needs to be used for 64 bit applications because wuw4.dll is a 32 bit DLL.  Wuwstub.exe adds only 28kb to your application's footprint.)

Next Steps...

Having integrated the Software Update Wizard with your code, the next step is to write your first update script: