Hello, The recently announced post-review version of Boost.Flyweight depends on some material (boost::swap) that is present in Boost SVN trunk but has not been officially released yet. To make Boost.Flywewight work with Boost 1.36, you just have to add the missing material to your local Boost directory. This material is packed for your convenience in a file named flyweight_compatibility_pack_1_36.zip located at the Vault: http://tinyurl.com/hrdm6 http://www.boost-consulting.com/vault/index.php?&direction=0&order=&directory=Patterns Best regards, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo