title: Unmanaged Exports System.MissingMethodException
body: <p>I have two functions getStatus() and checkStatus() that I have exposed using UnmanagedExports. I can successfully call them separately from C++ code. But when I call the first function getStatus() from inside the second function checkStatus() I get MissingMethodException. Following code for independent functions works fine:</p>
  
  <pre><code>[DllExport(ExportName = "GetStatusMethod", CallingConvention = CallingConvention.StdCall)]
  [return: MarshalAs(UnmanagedType.LPWStr)]
  public static string getStatus([MarshalAs(UnmanagedType.LPWStr)]string Url)
  {
      string status;
      //performing some action
      return status;
  }
  
  [DllExport(ExportName = "CheckStatusMethod", CallingConvention = CallingConvention.StdCall)]
  [return: MarshalAs(UnmanagedType.LPWStr)]
  public static string checkStatus([MarshalAs(UnmanagedType.LPWStr)]string someStr)
  {
      string status;
      //performing some action
      return status;
  }
  </code></pre>
  
  <p>Following throws MissingMethodException:</p>
  
  <pre><code>[DllExport(ExportName = "GetStatusMethod", CallingConvention = CallingConvention.StdCall)]
  [return: MarshalAs(UnmanagedType.LPWStr)]
  public static string getStatus([MarshalAs(UnmanagedType.LPWStr)]string Url)
  {
      string status;
      //performing some action
      return status;
  }
  
  [DllExport(ExportName = "CheckStatusMethod", CallingConvention = CallingConvention.StdCall)]
  [return: MarshalAs(UnmanagedType.LPWStr)]
  public static string checkStatus([MarshalAs(UnmanagedType.LPWStr)]string someStr)
  {
      return getStatus();// throws MissingMethodException
  }
  </code></pre>
  
  <p>How to call a function (that is exposed using UnmanagedExports) from within another exposed function in c#?</p>