diff --git a/clients/qt4/qt4client.cpp b/clients/qt4/qt4client.cpp
index bd7e0b44..630ed0c2 100644
--- a/clients/qt4/qt4client.cpp
+++ b/clients/qt4/qt4client.cpp
@@ -2907,7 +2907,7 @@ bool QtClient::getProperty(QObject* obj, const char* name, String& value)
 }
 
 // Copy a string list to a list of parameters
-void QtClient::copyParams(NamedList& dest, QStringList& src)
+void QtClient::copyParams(NamedList& dest, const QStringList& src)
 {
     for (int i = 0; i < src.size(); i++) {
 	if (!src[i].length())
diff --git a/clients/qt4/qt4client.h b/clients/qt4/qt4client.h
index ddbd4f0b..92fe367e 100644
--- a/clients/qt4/qt4client.h
+++ b/clients/qt4/qt4client.h
@@ -299,7 +299,7 @@ public:
      * @param dest Destination list
      * @param src Source string list
      */
-    static void copyParams(NamedList& dest, QStringList& src);
+    static void copyParams(NamedList& dest, const QStringList& src);
 
     /**
      * Copy a list of parameters to string list