Использование C-шной DLL

Автор: Xavier Pacheco

unit Main;

interface

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

type
  TMainForm = class(TForm)
    Button1: TButton;
    Button2: TButton;
    FooData: TEdit;
    Button3: TButton;
    Button4: TButton;
    SetCVarData: TEdit;
    GetCVarData: TEdit;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;
  _GlobalVar: PChar = 'This is a Delphi String';

implementation

uses PasStrng;

{$R *.DFM}

{$L ccode.obj}

type
  TFoo = class
    function Function1(Str1: PChar): integer; virtual; cdecl; abstract;
    function Function2(i: integer): integer; virtual; cdecl; abstract;
  end;

  PCharArray = ^TCharArray;
  TCharArray = array[0..127] of char;

  // import from OBJ file:

function _SAYHELLO(Text: PChar): Integer; cdecl; external;
procedure _C_VAR; external; // trick to import OBJ data

// imports from DLL file:

function ClassFactory: TFoo; cdecl; external 'cdll.dll'
  name '_CLASSFACTORY';

procedure ClassKill(Foo: TFoo); cdecl; external 'cdll.dll'
  name '_CLASSKILL';

procedure TMainForm.Button1Click(Sender: TObject);
begin
  _SayHello('hello world');
end;

procedure TMainForm.Button2Click(Sender: TObject);
var
  Foo: TFoo;
begin
  Foo := ClassFactory;
  Foo.Function1('huh huh, cool.');
  FooData.Text := IntToStr(Foo.Function2(10));
  ClassKill(Foo);
end;

function GetCArray: string;
var
  A: PCharArray;
begin
  A := PCharArray(@_C_VAR);
  Result := A^;
end;

procedure SetCArray(const S: string);
var
  A: PCharArray;
begin
  A := PCharArray(@_C_VAR);
  StrLCopy(A^, PChar(S), SizeOf(TCharArray));
end;

procedure TMainForm.Button3Click(Sender: TObject);
begin
  SetCArray(SetCVarData.Text);
end;

procedure TMainForm.Button4Click(Sender: TObject);
begin
  GetCVarData.Text := GetCArray;
end;

end.