[Boost-users] [ASIO] Windows native type for ASIO serial port?

I have a boost::asio::serial_port object. What is the specific Windows type returned by native()? I'm having trouble with my serial communication across the serial port, and want to get more diagnostic information by going to the native level. The serial port hangs occasionally on a synchronous read_some call, and I haven't been able to figure out why. Ideally, I'd like to build a timeout into the synchronous call. Any help is appreciated, Jeff Diewald JEOL USA