The example section in the documentation for boost::asio::streambuf indicates you can: boost::asio::streambuf::const_buffers_type bufs = b.prepare(512); The compiler (gcc) thinks not. You can however: boost::asio::streambuf::const_buffer_type bufs( b.prepare(512) ); Regards - michael -- ---------------------------------- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com