Delphi2010 调用 delphi6，7 dll的PChar参数的兼容问题

Delphi2010 CallFunction:

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls;

type

TForm1 = class(TForm)

btn1: TButton;

btn2: TButton;

procedure btn1Click(Sender: TObject);

procedure btn2Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

function MyFunction(s:PAnsiChar):Integer;stdcall;external 'MyDll';

//function MyFunction(s:PChar):Integer;stdcall;external 'MyDll';

var

Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);

begin

MyFunction(PAnsiChar('hello')); //'hello'

//MyFunction(PChar('hello')); //'h'

end;

end.

Delphi6 DllFunction:

library MyDll;

{ Important note about DLL memory management: ShareMem must be the

first unit in your library's USES clause AND your project's (select

Project-View Source) USES clause if your DLL exports any procedures or

functions that pass strings as parameters or function results. This

applies to all strings passed to and from your DLL--even those that

are nested in records and classes. ShareMem is the interface unit to

the BORLNDMM.DLL shared memory manager, which must be deployed along

with your DLL. To avoid using BORLNDMM.DLL, pass string information

using PChar or ShortString parameters. }

uses

SysUtils,

Classes,

Dialogs;

{$R *.res}

function MyFunction(s:PChar):Integer;stdcall;export;

begin

ShowMessage(s);

end;

exports MyFunction;

begin

end.