C#调用C++提供的dll出现的问题

我使用c++提供的dll调用的时候出现这个问题
运行库遇到了错误。此错误的地址为 0x79e71bd7，在线程 0x11f0 上。错误代码为 0xc0000005。此错误可能是 CLR 中的 bug，或者是用户代码的不安全部分或不可验证部分中的 bug。此 bug 的常见来源包括用户对 COM-interop 或 PInvoke 的封送处理错误，这些错误可能会损坏堆栈。
c++的结构为
function GetPosStatus(IP: PChar; Port: Integer; AQryGateWay: PQryGateWayInfoRet): Integer; export; stdcall;

PQryGateWayInfoRet = ^TQryGateWayInfoRet;
TQryGateWayInfoRet = packed record
BasicResponse: TBasicResponse;
RunInfo: TtagINFORUN;
DebugInfo: TtagINFODebug;
end;

TtagINFORUN = packed record
bLoginOK: Integer;
bGetFLowNoOK: Integer;
bDispInitOK: Integer;
PrivateSign: LongWord;
CtlStatus: Char;
ErrInfo: array[0..127] of char;
PosStatus: array[0..127] of Byte;
StatusBar485: Byte;
CurrDineNo: Byte;
end;
TtagINFODebug = packed record
FlowHead: LongWord；
FlowTail: LongWord;
CurrFlowNo: LongWord;
SNo: LongWord;
end;
C#为：
[DllImport("GateWayDll.dll")]
public static extern int GetPosStatus(byte[] ip,int port,ref TQryGateWayInfoRet ps);

[StructLayout(LayoutKind.Sequential)]
public struct TtagINFODebug
{
public UInt32 FlowHead;
public UInt32 FlowTail;
public UInt32 CurrFlowNo;
public UInt32 SNo;
}


[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct TQryGateWayInfoRet
{
public TBasicResponse tbRes;
public TtagINFORUN tgRun;
public TtagINFODebug tgDebug;
}
[StructLayout(LayoutKind.Sequential)]
public struct TtagINFORUN
{
public UInt16 bLoginOK;
public UInt16 bGetFLowNoOK;
public UInt16 bDispInitOK;
public UInt32 PrivateSign;
public byte CtlStatus;
[MarshalAs(UnmanagedType.LPTStr, SizeConst = 128)]
public string ErrInfo;
[MarshalAs(UnmanagedType.ByValArray, SizeConst = 128)]
public byte[] PosStatus;
public byte StatusBar485;
public byte CurrDineNo;
}
[StructLayout(LayoutKind.Sequential)]
public struct TBasicResponse
{
[MarshalAs(UnmanagedType.LPTStr, SizeConst = 3)]
public string TranCode;
public UInt16 RetCode;
}