Serializing objects, using __sleep and __wakeup?

I have a few classes in my CORBA extension, and I want them to work transparently with PHP:s session management, they need to be serializable. Right now I believe that value.obj.properties is serialized, but there I just store an index to a list of internal data... (like the COM extension) I looked in ext/session/session.c and ext/standard/var.c and it seems like it is possible to make member functions called __sleep and __wakeup, which might be what I need. Can anyone explain how these work? I have not been able to find any docs or examples that explain this. Regards, -\- David Eriksson -/- "An expert in a particular computer language is really an expert in the work-arounds necessary to use this language to perform useful work." - Richard B. Johnson