Obtaining address locations of an overload method

问题:

How do I get all the address locations for functions/procedures/methods that is overloaded?

For example, Dialogs.MessageDlgPosHelp is overloaded having two different versions of it - one without a default button and one with. How would I obtain the address locations for the two functions?

回答1:

Based on this thread and what Thomas Mueller pointed there, you might define types with the same signatures as methods whose addresses you want to obtain (for each overload). If you then declare the variables of those types and assign method pointers to them you will make sure that compiler chooses the right overload to your known variable type and moreover that it won't ignore them if they wouldn't be used anywhere in the code (some overloads might not get linked in your binary).

So based on his idea it might looks for the MessageDlgPosHelp function overloads like this:

type
  TMessageDlgPosHelp1 = function(const Msg: string; DlgType: TMsgDlgType;
    Buttons: TMsgDlgButtons; HelpCtx: Longint; X, Y: Integer;
    const HelpFileName: string): Integer;
  TMessageDlgPosHelp2 = function(const Msg: string; DlgType: TMsgDlgType;
    Buttons: TMsgDlgButtons; HelpCtx: Longint; X, Y: Integer;
    const HelpFileName: string; DefaultButton: TMsgDlgBtn): Integer;

procedure TForm1.Button1Click(Sender: TObject);
var
  MessageDlgPosHelp1: TMessageDlgPosHelp1;
  MessageDlgPosHelp2: TMessageDlgPosHelp2;
begin
  MessageDlgPosHelp1 := MessageDlgPosHelp;
  MessageDlgPosHelp2 := MessageDlgPosHelp;
  ShowMessage(Format('%p; %p', [@MessageDlgPosHelp1, @MessageDlgPosHelp2]));
end;

回答2:

Also You can create derived class that will expose this overload methods as simple methods with different names, cast any instance of that class to new class and easily use address of your wrapper methods.