A while back I wrote some code which made heavy use of small boost::functions, using Boost 1.33.1. The performance hit was pretty grim, and in the end I had to take thme out and use non generic hand rolled solutions. However, we have recently upgraded to Boost 1.37, and I notive from all the Boost version issue docs that a small function optimization was added in n Boost 1.35. Can anyone tell me in general terms what was done, and possibly if I'm likely to find the performance significantly better now. Many Thanks, Rob.