[Boost-users] [variant] is the which() function part of variant's public API?

which() is a public member function of variant, but I don't see any mention of it in the documentation. Can I assume this is part of the public API (i.e. it won't go away, won't change its behaviour in future releases) or not? (For example, I am writing a function to serialize a variant and thinking that one implementation might be to write the which() followed by the object). Thanks, Nate