unit Unit1;

interface

uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type

  TForm1 = class(TForm)

    btn1: TButton;

    btn2: TButton;

    procedure btn1Click(Sender: TObject);

    procedure btn2Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

var

  Form1: TForm1;

  function add(a:integer;b:integer):integer;cdecl;external 'mydllForDelphi.dll' ;

  function sub(a:integer;b:integer):integer;cdecl;external 'mydllForDelphi.dll' ;

implementation

{$R *.dfm}

//mydllForDelphi.dll  c++写的dll中的代码

// extern "C" __declspec(dllexport) int add(int a, int b)

//{

//    return (a + b);

//}

//

//extern "C" __declspec(dllexport) int sub(int a, int b)

//{

//    return (a - b);

//}

procedure TForm1.btn1Click(Sender: TObject);

begin

  self.caption:= inttostr(add(,));

  self.caption:=self.caption+'///' +inttostr(sub(,));

end;

procedure TForm1.btn2Click(Sender: TObject);

//  function add(a:integer;b:integer):integer;cdecl;external 'mydllForDelphi.dll' ;

type

  TIntFunc=function(a:integer;b:integer):integer;cdecl; //cdecl 不能少

var

  Th: Thandle;

  Tf:TIntFunc;

  Tp,tp2:TFarProc ;

begin

  Th:= loadlibrary('mydllForDelphi.dll');

  if Th > then

  try

    Tp:=GetProcAddress(Th, PChar('add'));

    if Tp<>nil then

    begin

      Tf:=TIntFunc(Tp);

      Self.Caption:=IntToStr(Tf(,)); {调用TestC函数}

    end;

    Tp2:=GetProcAddress(Th, PChar('sub'));

    if Tp2<>nil then

    begin

      Tf:=TIntFunc(Tp2);

      Self.Caption:=Self.Caption+'|||'+IntToStr(Tf(,)); {调用TestC函数}

    end;

  finally

    freelibrary(th);

  end;

end;

end.