Hello, I need to use gcc 4.0 and circular buffer. But this latter seems unusuable with gcc 4.0. It gives a lots of error messages. Here is the 2 irst error messages: in debug.hpp: /home/torri/local/include/boost-1_33/boost/circular_buffer/debug.hpp:60: error: invalid use of undefined type 'const struct boost::cb_details::cb_iterator_base' /home/torri/local/include/boost-1_33/boost/circular_buffer/debug.hpp:22: error: forward declaration of 'const struct boost::cb_details::cb_iterator_base' the 2 classes in debug.hpp are cross-referenced. It seems that the forward declaration is not sufficient for gcc 4.0. in base.hpp: /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: using typedef-name 'boost::circular_buffer::iterator' after 'struct' /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:105: error: 'boost::circular_buffer::iterator' has a previous declaration here /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: friend declaration does not name a class or function gcc 4.0 doesn't like the 'struct' word. Putting the 'class' word instead of struct gives error too: /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: a class-key must be used when declaring a friend /home/torri/local/include/boost-1_33/boost/circular_buffer/base.hpp:139: error: friend declaration does not name a class or function Does someone see solutions for these problems ? Jan: it would be great if you try to finish circular buffer :) thank you Vincent Torri