diff --git a/src/StdString.h b/src/StdString.h
index 43c23b9c61..17f7946dc9 100644
--- a/src/StdString.h
+++ b/src/StdString.h
@@ -770,6 +770,10 @@ public:
 	  return MYBASE::operator[](static_cast<MYSIZE>(nIdx));
 	}
 	
+	CT& operator[](long long unsigned int nIdx){
+	  return MYBASE::operator[](static_cast<MYSIZE>(nIdx));
+	}
+	
 	const CT& operator[](long long unsigned int nIdx) const {
 	  return MYBASE::operator[](static_cast<MYSIZE>(nIdx));
 	}