Dll 使用 PChar 参数的小例子

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本例效果图:

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Dll 文件:

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library Lib;

uses
  SysUtils, Classes;

{$R *.res}

procedure Test(p: PChar);
const
  Title = 'Title ';
var
  str: string;
begin
  str := p;
  StrCopy(p, Title);
  StrCat(p, PChar(str));
end;

exports Test;

begin
end.

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调用的代码文件:

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unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  end;

var
 Form1: TForm1;

implementation

{$R *.dfm}

procedure Test(p: PChar); external 'Lib.dll';

var num: Integer;

procedure TForm1.Button1Click(Sender: TObject);
var
  p: PChar;
begin
  Inc(num);
  p := StrAlloc(255);
  StrCopy(p, PChar(IntToStr(num)));
  Test(p);
  Text := p;
  StrDispose(p);
end;

end.

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