diff --git a/include/json/reader.h b/include/json/reader.h
index 111e5dd..0f489d6 100644
--- a/include/json/reader.h
+++ b/include/json/reader.h
@@ -378,7 +378,7 @@
 bool JSON_API parseFromStream(CharReader::Factory const&,
                               IStream&,
                               Value* root,
-                              std::string* errs);
+                              String* errs);
 
 /** \brief Read from 'sin' into 'root'.