The macro BOOST_ASIO_DISABLE_BUFFER_DEBUGGING is not defined default.Then the boost/asio/buffer.hpp will include the boost/function.hpp with pack 8 in MSVC.If the golable envionment is using pack 4 and also use boost/function.hpp, then the class function_base maybe use different pack on different place in same project. It result crash which is hardly to find the reason. In order to resolve problem, I defined the BOOST_ASIO_DISABLE_BUFFER_DEBUGGING in my project. Then it's be ok. I consider the BOOST_ASIO_DISABLE_BUFFER_DEBUGGING should be defined by default, or there should be another resolution. Qiu Yuzhou Epic Games China MSN: qbowater@163.com Gtalk: qbowater@gmail.com