Hello, I'm reading in the documentation that barrier::wait may throw thread_resource_error. Looking at the source, it uses condition_variable::wait, which in turn (I think) throws nothing on windows, but may throw boost::condition_error under pthread. So the documentation appears to be wrong. But also, I am puzzled why would wait() throw anything but boost::thread_interrupted? Let's say I have two threads call wait() on a barrier, and one of them throws an error. What am I supposed to do with that exception? How can I recover from such a failure? I am not an expert but I think that if the exception is used to report a bug in user code, it would be better to assert() instead of throwing an exception. One final note, Boost Thread doesn't use boost::throw_exception to throw exceptions. This means that the exception_ptr functionality in Boost Exception is crippled for exceptions emitted by Boost Thread. This is unfortunate because transporting exception objects between threads is a key motivation for boost::exception_ptr; see http://svn.boost.org/svn/boost/trunk/libs/exception/doc/cloning.html. Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode