c#调用c++dll参数问题

[liuhaisong290]

//c++函数：
CMT_DLL_API XsensResultValue cmtDataGetOriEuler(const int32_t instance, CmtEuler* data, const CmtDeviceId dev=0, void* bundle=NULL);
//CmtEuler 是结构
struct CmtEuler {
double m_roll; //!< The roll (rotation around x-axis / back-front-line)
double m_pitch; //!< The pitch (rotation around y-axis / right-left-line)
double m_yaw; //!< The yaw (rotation around z-axis / down-up-line)
};
//! The type of a Device Id
typedef uint32_t CmtDeviceId;


求解在c#中要怎么调用这个函数，下附我自己写的函数
public static extern XsensResultValue cmtDataGetOriEuler(int instance, ref CmtEuler data, int dev);
[StructLayout(LayoutKind.Explicit)]
public struct CmtEuler
{
[FieldOffset(0)]
public double m_roll;//!< The roll (rotation around x-axis / back-front-line)
[FieldOffset(4)]
public double m_pitch;//!< The pitch (rotation around y-axis / right-left-line)
[FieldOffset(8)]
public double m_yaw;//!< The yaw (rotation around z-axis / down-up-line)
}
出现下面的错误，请大牛帮忙

[bdmh]

调用约定一致吗， [DllImport(@"BaseEn.dll",CallingConvention= CallingConvention.Cdecl)]

[liuhaisong290]

一致 我已经写了几个函数了，这个函数出现了结构和可选参数 我也不知道怎么办了

[liuhaisong290]

有没有大牛来解答呢？

[liuhaisong290]

自己顶起来!