.. module:: tornado.platform.caresresolver
This module contains a DNS resolver using the c-ares library (and its
wrapper pycares
).
.. py:class:: CaresResolver Name resolver based on the c-ares library. This is a non-blocking and non-threaded resolver. It may not produce the same results as the system resolver, but can be used for non-blocking resolution when threads cannot be used. c-ares fails to resolve some names when ``family`` is ``AF_UNSPEC``, so it is only recommended for use in ``AF_INET`` (i.e. IPv4). This is the default for ``tornado.simple_httpclient``, but other libraries may default to ``AF_UNSPEC``.