Access Violation Exception in c#

Question

hi friend,

       When I call the C++ dll function, the following error occurred:

   Error Message=Attempts to read from or write to protected memory. This is often an indication that other memory is corrupt.

 

C++ codes:

string test(string s[]){

string t="";

 

for(int i=0;i<2;i++){

   t+=s[i];

}

 

return t;

}

 

C# codes:

class Program

{    

     [DllImport("safeTest.dll", CallingConvention = CallingConvention.Cdecl)]

public static extern string test(string[] s);

static void Main(string[] args)

{

string[] city = { "London ", "San Francisco " };

string temp = test(city);

Console.WriteLine(temp);

Console.ReadKey();

}

}

 

Thanks.