Umm I just realized that the implementation I posted (see my other post) hasn't been fully tested. I had written another implementation which added the allocator parameter where necessary, and the allocator-less code simply passed an std::allocator where allocator was required. This means that even when the user does not supply an allocator, the allocator code is still instantiated in the tests (even though the allocator might not get used due to optimizations.) In the implementation I posted, I opted for a parallel line of allocator support functions next to the original allocator-less functions. I liked this better because no allocator-related stuff is ever instantiated unless the user passes an allocator (and most users don't.) The problem is that most boost::function tests do not use allocators. So while the allocator code should work (because it got tested in its original form), in it's current form it has only been proven to pass the allocator_test.cpp, which is rather simplistic. To really test everything, one needs to run all tests with the following variations: - pointer to function - pointer to member function - function object that fits the small object optimization - function object that does not fit the small object optimization - all of the above variations using an user-supplied allocator. Emil Dotchevski