1``tornado.platform.caresresolver`` --- Asynchronous DNS Resolver using C-Ares 2============================================================================= 3 4.. module:: tornado.platform.caresresolver 5 6This module contains a DNS resolver using the c-ares library (and its 7wrapper ``pycares``). 8 9.. py:class:: CaresResolver 10 11 Name resolver based on the c-ares library. 12 13 This is a non-blocking and non-threaded resolver. It may not produce 14 the same results as the system resolver, but can be used for non-blocking 15 resolution when threads cannot be used. 16 17 c-ares fails to resolve some names when ``family`` is ``AF_UNSPEC``, 18 so it is only recommended for use in ``AF_INET`` (i.e. IPv4). This is 19 the default for ``tornado.simple_httpclient``, but other libraries 20 may default to ``AF_UNSPEC``. 21