Hello, I've been going through the Boost libraries and encountered boost::circular_buffer. My question is not with the operation of Boost.Circular Buffer as-such, but about how the instantiation of it works without specifying the allocator. The introductory example in the documentation(http://www.boost.org/doc/libs/1_35_0/libs/circular_buffer/doc/circular_buffe...) contains the following line: // Create a circular buffer with a capacity for 3 integers. boost::circular_buffer<int> cb(3); But looking at the header file base.hpp in the circular_buffer directory, we have the following: template <class T, class Alloc> class circular_buffer { ...... }; The Alloc template parameter is not a default one, so I can't understand how we can instantiate cb in the example? Apologies if this is not strictly boost-user related. Regards, Jim