Hey, The lockfree::queue constructors raise a static assert if no capacity is specified. This contradicts the member initialization code close to the assert, for instance: queue(void): head_(tagged_node_handle(0, 0)), tail_(tagged_node_handle(0, 0)), pool(node_allocator(), has_capacity ? capacity : 0) { BOOST_STATIC_ASSERT(has_capacity); initialize(); } which implies that 'has_capacity' is allowed to be false. From what I can see 'has_capacity' could be false, indeed, in particular if the queue is not bounded in size. Would changing this to queue(void): head_(tagged_node_handle(0, 0)), tail_(tagged_node_handle(0, 0)), pool(node_allocator(), has_capacity ? capacity : 0) { BOOST_STATIC_ASSERT(has_capacity || capacity); initialize(); } reflect the actual intention? Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu