diff --git a/BaseLib/IO/XmlIO/Qt/XMLQtInterface.h b/BaseLib/IO/XmlIO/Qt/XMLQtInterface.h
index 4426d8cc6c570edd798e42c02421fdeb4c49cc14..b437c8502665c99f3d7aea25e248965a2a76b378 100644
--- a/BaseLib/IO/XmlIO/Qt/XMLQtInterface.h
+++ b/BaseLib/IO/XmlIO/Qt/XMLQtInterface.h
@@ -30,7 +30,7 @@ namespace IO
 class XMLQtInterface
 {
 public:
-    XMLQtInterface(QString schemaFile = "");
+    explicit XMLQtInterface(QString schemaFile = "");
     virtual ~XMLQtInterface() = default;
 
     /// As QXMLStreamWriter seems currently unable to include style-file links into xml-files, this method will workaround this issue and include the stylefile link.