diff --git a/pygccxml/parser/scanner.py b/pygccxml/parser/scanner.py
index <HASH>..<HASH> 100644
--- a/pygccxml/parser/scanner.py
+++ b/pygccxml/parser/scanner.py
@@ -322,7 +322,7 @@ class scanner_t( xml.sax.handler.ContentHandler ):
         if isinstance( calldef, declaration_t ):

             calldef.name = attrs.get(XML_AN_NAME, '')

             calldef.has_extern = attrs.get( XML_AN_EXTERN, False )

-            throw_stmt = attrs.get( XML_AN_THROW, "" )

+            throw_stmt = attrs.get( XML_AN_THROW, None )

             if None is throw_stmt:

                 calldef.does_throw = True

                 calldef.exceptions = []
adding warning and xml cache