boost::asio 1.4.3的linux实现总算采用epoll的et模式了

Asio:

• Improved performance.
• Reduced compile times.
• Reduced the size of generated code.
• Extended the guarantee that background threads don't call user code to all asynchronous operations (#3923).
• Changed to use edge-triggered epoll on Linux.
• Changed to use timerfd for dispatching timers on Linux, when available.
• Changed to use one-shot notifications with kqueue on Mac OS X and BSD platforms.
• Added a bitmask type ip::resolver_query_base::flags as per the TR2 proposal. This type prevents implicit conversion from int to flags, allowing the compiler to catch cases where users incorrectly pass a numeric port number as the service name.
• Added #define NOMINMAX for all Windows compilers. Users can define BOOST_ASIO_NO_NOMINMAX to suppress this definition (#3901).
• Fixed a bug where 0-byte asynchronous reads were incorrectly passing an error::eof result to the completion handler (#4023).
• Changed the io_control() member functions to always call ioctl on the underlying descriptor when modifying blocking mode (#3307).
• Changed the resolver implementation to longer require the typedefs InternetProtocol::resolver_query and InternetProtocol::resolver_iterator, as neither typedef is part of the documented InternetProtocol requirements. The corresponding typedefs in the ip::tcp, ip::udp and ip::icmp classes have been deprecated.
• Fixed out-of-band handling for reactors not based on select().
• Added new BOOST_ASIO_DISABLE_THREADS macro that allows Asio's threading support to be independently disabled.
• Minor documentation improvements.