library dll;
uses
  SysUtils, Classes, Messages, Dialogs;
{$R *.res}
function ErrorMessage: String; stdcall;
begin
  MessageDlg('About', mtInformation, [mbOK],0);
end;
exports ErrorMessage;
  begin
  end.

unit main;

interface

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

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

var
  Form1: TForm1;

implementation


{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
type
  TMyFunc = procedure;
var
  DLLInstance  : THandle;
begin
  DLLInstance := LoadLibrary(PChar('dll.dll'));
  if (DLLInstance = 0) then begin
  MessageDlg('Невозможно загрузить DLL', mtError, [mbOK], 0);
  Application.Terminate;
  end
  else
  FreeLibrary(DLLInstance);
end;
procedure TForm1.Button1Click(Sender: TObject);
type
  TMyFunc = procedure;
var
  ErrorMessage: TMyFunc;
  DLLInstance  : THandle;
begin
  DLLInstance := LoadLibrary(PChar('dll.dll'));
  @ErrorMessage := GetProcAddress(DLLInstance, 'ErrorMessage');
  ErrorMessage( );
  FreeLibrary(DLLInstance);
  ShowMessage('Test');
  end;
end.