I am trying to use the macro : BOOST_CLASS_EXPORT(A) and the compiler issue the warning: warning #880: omission of explicit type is nonstandard ("int" assumed) Also I have to change to BOOST_CLASS_EXPORT(A); in order to compile, but I do not think the semicolon is in the example. --------------------------------- Brings words and photos together (easily) with PhotoMail - it's free and works with Yahoo! Mail.