def current(instance=True):
        """Returns the current thread's `IOLoop`.

        If an `IOLoop` is currently running or has been marked as
        current by `make_current`, returns that instance.  If there is
        no current `IOLoop` and ``instance`` is true, creates one.

        .. versionchanged:: 4.1
           Added ``instance`` argument to control the fallback to
           `IOLoop.instance()`.
        .. versionchanged:: 5.0
           The ``instance`` argument now controls whether an `IOLoop`
           is created automatically when there is none, instead of
           whether we fall back to `IOLoop.instance()` (which is now
           an alias for this method)
        """
        current = getattr(IOLoop._current, "instance", None)
        if current is None and instance:
            current = None
            #if asyncio is not None:
            #    from tornado.platform.asyncio import AsyncIOLoop, AsyncIOMainLoop
            #    if IOLoop.configured_class() is AsyncIOLoop:
            #        current = AsyncIOMainLoop()
            if current is None:
                if sys.platform == 'darwin':
                    from .platforms import KQueueIOLoop
                    current = KQueueIOLoop()
                else:
                    from .platforms import EPollIOLoop
                    current = EPollIOLoop()
                current.initialize()
                #current = IOLoop()
            if IOLoop._current.instance is not current:
                raise RuntimeError("new IOLoop did not become current")
        return current
def current ( instance = True ) : current = getattr ( IOLoop . _current , "instance" , None ) if current is None and instance : current = None if current is None : if sys . platform == 'darwin' : from . platforms import KQueueIOLoop current = KQueueIOLoop ( ) else : from . platforms import EPollIOLoop current = EPollIOLoop ( ) current . initialize ( ) if IOLoop . _current . instance is not current : raise RuntimeError ( "new IOLoop did not become current" ) return current
Returns the current thread's `IOLoop`.

        If an `IOLoop` is currently running or has been marked as
        current by `make_current`, returns that instance.  If there is
        no current `IOLoop` and ``instance`` is true, creates one.

        .. versionchanged:: 4.1
           Added ``instance`` argument to control the fallback to
           `IOLoop.instance()`.
        .. versionchanged:: 5.0
           The ``instance`` argument now controls whether an `IOLoop`
           is created automatically when there is none, instead of
           whether we fall back to `IOLoop.instance()` (which is now
           an alias for this method)