VC++程序转delphi程序出问题,高手指点一二

[cp1982]

VC++代码如下:
typedef struct{
BYTE m_bRemoteChannel;
BYTE m_bSendMode;
BYTE m_bRight;
char *m_sIPAddress;
char *m_sUserName;
char *m_sUserPassword;
BOOL m_bUserCheck;
DISPLAY_PARA displaypara;
}CLIENT_CARDINFO, *PCLIENT_CARDINFO;

CPLAYER_API LONG __stdcall MP4_ClientStart_Card(PCLIENT_CARDINFO pClientinfo,long nChannelNum,void(CALLBACK *ReadDataCallBack)(DWORD nPort,UCHAR *pPacketBuffer,DWORD nPacketSize));

void CClientdemoDlg::OnButton1()
{
CLIENT_CARDINFO aa5;
.
.
MP4_ClientStart_Card(&aa5,0,NULL);
.
.
}

VC调用成功的,我写成delphi后调用不成功,大家帮我看看哪里有问题
TCLIENT_CARDINFO=record
m_bRemoteChannel:byte;
m_bSendMode:TConnectMode;
m_bRight:byte;
m_sIPAddress:pchar;
m_sUserName:pchar;
m_sUserPassword:pchar;
m_bUserCheck:boolean;
displaypara:tDISPLAY_PARA;
end;
PCLIENT_CARDINFO=^TCLIENT_CARDINFO;

function MP4_ClientStart_Card(pclientinfo:pclient_cardinfo;nChannelNum:longint;ReadDataCallBack:TReadDataCallBack):longint;stdcall;//这里有问题
begin
Result:=-1;
if Init_HikNet<>1 then
exit;
if not Assigned(VMP4_ClientStart_Card) then
@VMP4_ClientStart_Card:=GetProcAddress(HIKDecodeDLL,'MP4_ClientStart_Card');
if @VMP4_ClientStart_Card<>nil then
Result:=VMP4_ClientStart_Card(pClientinfo,nChannelNum,ReadDataCallBack);
end;

调用不成功的
procedure TForm1.Button1Click(Sender: TObject);
var
aa5:tclient_cardinfo;
begin
.
.
MP4_ClientStart_Card(@aa5,1,null);
.
.
end;
出错信息为
[Error] Unit1.pas(76): Incompatible types: 'Calling conventions differ'
大家帮我看看是什么原因啊,求求高手指点一二了

[cp1982]

我自己顶一下

[phalcon]

null -> nil trytry

[cp1982]

我再顶自己一下,没人帮帮我嘛

[cp1982]

OK,现在已经解决了,谢谢phalcon兄,是这个问题,谢了,结贴

[anikan_yu]

delphi默认的函数调用的压栈方式是__fastcall， 明显你的库函数是__stdcall，
在delphi中你要对ReadDataCallBack这个函数指针说明压栈的方式

[cp1982]

我现在的错误是在@aa5这个地方,我写成^aa5也不对