diff --git a/src/xml/xml.cpp b/src/xml/xml.cpp
index b61c223955..6cf9080002 100644
--- a/src/xml/xml.cpp
+++ b/src/xml/xml.cpp
@@ -143,6 +143,8 @@ bool wxXmlNode::HasProp(const wxString& propName) const
 
 bool wxXmlNode::GetPropVal(const wxString& propName, wxString *value) const
 {
+    wxCHECK_MSG( value, false, "value argument must not be NULL" );
+
     wxXmlProperty *prop = GetProperties();
 
     while (prop)