Help to create a Dll and pass a string to it.

Hello guys,

I create a simple dll and application that I only call a method and it display " hello world ".

Now I need to create a function where I can pass a string to it and do it display my message, take a look at my code:

Dll created

library DllCrystal;

uses
  SysUtils,
  Classes,
  Dialogs;

{$R *.res}

procedure DllMessage; export;
begin
  ShowMessage('Hello world from a Delphi DLL') ;
end;
 
 exports DllMessage;

begin
end.

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My application that calls the DLL

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  procedure DllMessage; external 'DllCrystal.dll';

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  DllMessage
end;

end.

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Now, I need a simple help from you how to do that, create a correct function and call the function in application passing the value to it.

thanks a lot
alex