c# 調用 c++的 dll 中關於 char*傳入傳出參數

c++的dll接口原型為：int CheckSN(const char* InfoList, char* msg);

c#調用轉換為：

[DllImport("sncplusInterface.dll", EntryPoint = "CheckSN", ExactSpelling = false, CallingConvention = CallingConvention.Cdecl)]
public static extern int CheckSN(string InfoList, StringBuilder msg);

調用為：

StringBuilder chOutMsg = new StringBuilder(1024);

CheckSN(chData, chOutMsg/*ref chOutMsg*/);

string str = chOutMsg.ToString();

用ref 或 out關鍵字會crash