maybe fix DLL symbols for VS
diff --git a/include/json/writer.h b/include/json/writer.h
index ed21c9b..2d6dbce 100644
--- a/include/json/writer.h
+++ b/include/json/writer.h
@@ -66,7 +66,7 @@
/** \brief Write into stringstream, then return string, for convenience.
* A StreamWriter will be created from the factory, used, and then deleted.
*/
-std::string writeString(StreamWriter::Factory const& factory, Value const& root);
+std::string JSON_API writeString(StreamWriter::Factory const& factory, Value const& root);
/** \brief Build a StreamWriter implementation.