unit Unit1;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, Forms, Controls, Graphics, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Memo1: TMemo;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private

  public

  end;

var
  Form1: TForm1;

implementation

{$R *.lfm}

uses uSimpleClassReg;

type
  TDllFunc = function: Boolean; stdcall;

procedure MakeReport(Dest: TMemo;
  DllInit, DllIsRegistered, DllRegister, DllUnRegister: TDllFunc);
var
  S: string;
begin
  Dest.Clear;
  WriteStr(S, 'Dll Init result = ', DllInit);
  Dest.Append(S);
  WriteStr(S, 'Is registered in EXE = ', IsClassRegistered(HInstance));
  Dest.Append(S);
  WriteStr(S, 'Regiser in EXE result = ', RegisterClass(HInstance));
  Dest.Append(S);
  WriteStr(S, 'Is registered in EXE = ', IsClassRegistered(HInstance));
  Dest.Append(S);
  WriteStr(S, 'Is registered in DLL = ', DllIsRegistered);
  Dest.Append(S);
  WriteStr(S, 'Regiser in DLL result = ', DllRegister);
  Dest.Append(S);
  WriteStr(S, 'Is registered in DLL = ', DllIsRegistered);
  Dest.Append(S);
  WriteStr(S, 'UnRegiser in DLL result = ', DllUnRegister);
  Dest.Append(S);
  WriteStr(S, 'Is registered in DLL = ', DllIsRegistered);
  Dest.Append(S);
  WriteStr(S, 'Is registered in EXE = ', IsClassRegistered(HInstance));
  Dest.Append(S);
  WriteStr(S, 'UnRegiser in EXE result = ', UnRegisterClass(HInstance));
  Dest.Append(S);
  WriteStr(S, 'Is registered in EXE = ', IsClassRegistered(HInstance));
  Dest.Append(S);
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  DllIsRegistered: TDllFunc;
  DllRegister: TDllFunc;
  DllUnRegister: TDllFunc;
  DllInit: TDllFunc;
  LibHandle: TLibHandle;
begin
  LibHandle := SafeLoadLibrary('project1Dll.dll');
  if LibHandle <> 0 then
  try
    DllIsRegistered := TDllFunc(GetProcAddress(LibHandle, 'DllIsRegistered'));
    DllRegister := TDllFunc(GetProcAddress(LibHandle, 'DllRegister'));
    DllUnRegister := TDllFunc(GetProcAddress(LibHandle, 'DllUnRegister'));
    DllInit := TDllFunc(GetProcAddress(LibHandle, 'DllInit'));
    if Assigned(DllInit) and Assigned(DllIsRegistered) and
      Assigned(DllRegister) and Assigned(DllUnRegister) then
    begin
      MakeReport(Memo1, DllInit, DllIsRegistered, DllRegister, DllUnRegister);
    end
    else
      ShowMessage('Get Proc Address failed!');
  finally
    UnloadLibrary(LibHandle);
  end
  else
    ShowMessage('Unable to load library!');
end;

function DllInit: Boolean; stdcall; external 'project1Dll.dll';
function DllIsRegistered: Boolean; stdcall; external 'project1Dll.dll';
function DllRegister: Boolean; stdcall; external 'project1Dll.dll';
function DllUnRegister: Boolean; stdcall; external 'project1Dll.dll';

procedure TForm1.Button2Click(Sender: TObject);
begin
  MakeReport(Memo1, @DllInit, @DllIsRegistered, @DllRegister, @DllUnRegister);
end;

end.