[fpc-pascal] THelpEvent usage and meaning of parameters?

[Marco van de Voort]

In our previous episode, Graeme Geldenhuys said:
> > BTW:
> > THelpEvent in Free Pascal has a totally different signature to the
> > THelpEvent type in Kylix 3. I'm not sure about Delphi VCL signature.
> 
> 
> Kylix 3 type signature:
>   THelpEvent = function(HelpType: THelpType; HelpContext: THelpContext;
>        const HelpKeyword: String; const HelpFile: String;
>        var Handled: Boolean): Boolean of object;
> 
> 
> Free Pascal type signature:
>   THelpEvent = function (Command: Word; Data: Longint;
>     var CallHelp: Boolean): Boolean of object;

This looks like chm (k3) vs older (.hlp) definition.