[Boost-users] Null Stream

Hi, I'm new at boost, but I don't know how to use the http://beta.boost.org/doc/libs/1_43_0/boost/iostreams/device/null.hpp device. I must use the boost::iostreams::copy to copy a stream to the /dev/ null, but I don't know to declare my out null-output stream. Can anyone help me to declare the stream? Thanks Phil