The author would like to thank everybody who gave suggestions and comments. Especially valuable were the contributions of Thorsten Ottosen, Jeff Garland and the other boost members who participated in the review process, namely David Abrahams, Daniel Frey, Beman Dawes, John Maddock, David B.Held, Pavel Vozenilek and many other. Additional thanks go to Stefan Slapeta and Toon Knapen, who have been very resourceful in solving various portability issues.