diff --git a/MString.cpp b/MString.cpp
index 8c1cb25..9db15ad 100644
--- a/MString.cpp
+++ b/MString.cpp
@@ -74,7 +74,7 @@ namespace coreutils {
 	free(data);
    }
    
-   MString &MString::operator=(coreutils::MString &value) {
+   MString &MString::operator=(coreutils::MString value) {
       setSize(value.getLength());
       memcpy(data, value.getData(), value.getLength());
       length = value.getLength();
diff --git a/MString.h b/MString.h
index 2735544..defc8a5 100644
--- a/MString.h
+++ b/MString.h
@@ -97,7 +97,7 @@ namespace coreutils
       
       //      MString& operator=(coreutils::ZString& data);
       
-      MString &operator=(coreutils::MString &data);
+      MString &operator=(coreutils::MString data);
       
       ///
       /// Assignment operator will copy data to backing store.
diff --git a/testing/jstring_test b/testing/jstring_test
index 92739c2..23fbe1d 100755
Binary files a/testing/jstring_test and b/testing/jstring_test differ
diff --git a/testing/mstring_test b/testing/mstring_test
index 3d0e9d2..9ec153b 100755
Binary files a/testing/mstring_test and b/testing/mstring_test differ