because regular C functions work differently than the Windows API functions; their "calling conventions" are different, meaning how they pass around parameters is different. (This was hinted at in the error.)
所以请在C#中 使用CallingConvention = CallingConvention.Cdecl)，代码如下：
[DllImport("CommonNativeLib.dll", CallingConvention = CallingConvention.Cdecl)]
或者 在C++中：
extern "C" __declspec(dllexport) int __stdcall Add(int a, int b) ...