Without this reset, starttls would fail if a connect/starttls was done after a
quit, because smtplib assumed the existing value of emspt_features was
accurate, but it gets reset when starttls completes (and the new value does
not contain the starttls capability, since tls is already started at that
point).  (There may be additional places where this lack of reset was an
issue as well.)

Patch by Milan Oberkirch.

Issue #22098: ctypes' BigEndianStructure and LittleEndianStructure now define an empty __slots__ so that subclasses don't always get an instance dict.

Patch by Claudiu Popa.

Issue #22185: Fix an occasional RuntimeError in threading.Condition.wait() caused by mutation of the waiters queue without holding the lock.

Patch by Doug Zongker.

Issue #22185: Fix an occasional RuntimeError in threading.Condition.wait() caused by mutation of the waiters queue without holding the lock.

Patch by Doug Zongker.

available (unlikely)

QueryPerformanceFrequency() cannot fail on Windows XP and later according to
its documentation: raise an exception on error and drop the fallback to the
system clock.

Other changes:

* The whole _PyTime API is private (not defined if Py_LIMITED_API is set)
* _PyTime_gettimeofday_info() also returns -1 on error
* Simplify PyTime_gettimeofday(): only use clock_gettime(CLOCK_REALTIME) or
  gettimeofday() on UNIX. Don't fallback to ftime() or time() anymore.

clock_gettime(CLOCK_REALTIME) if available. As a side effect, Python now
depends on the librt library on Solaris and on Linux (only with glibc older
than 2.17).

Patch by Claudiu Popa.

Patch by Claudiu Popa.

Don't raise a TimeoutError if we reached the timeout and the future completed
in the same iteration of the event loop. A side effect of the bug is that
Queue.get() looses items.

Don't raise a TimeoutError if we reached the timeout and the future completed
in the same iteration of the event loop. A side effect of the bug is that
Queue.get() looses items.

than a potentially risky preexec_fn=os.setsid call.

than a potentially risky preexec_fn=os.setsid call.

descriptor is in blocking mode.

Since a new demo can now be loaded while one is running,
adjust loadfile to do the same cleanup as stopIt.

with an external libmpdec.

operations regarding to non-blocking mode. The non-blocking mode does not
matter when using a ProactorEventLoop, only for SelectorEventLoop.

to non-blocking mode. The non-blocking mode does not matter when using a
ProactorEventLoop, only for SelectorEventLoop.

method

* PipeServer.close() now cancels the "accept pipe" future which cancels the
  overlapped operation.
* Fix _SelectorTransport.__repr__() if the transport was closed
* Fix debug log in BaseEventLoop.create_connection(): get the socket object
  from the transport because SSL transport closes the old socket and creates a
  new SSL socket object. Remove also the _SelectorSslTransport._rawsock
  attribute: it contained the closed socket (not very useful) and it was not
  used.
* Issue #22063: socket operations (sock_recv, sock_sendall, sock_connect,
  sock_accept) of the proactor event loop don't raise an exception in debug
  mode if the socket are in blocking mode. Overlapped operations also work on
  blocking sockets.
* Fix unit tests in debug mode: mock a non-blocking socket for socket
  operations which now raise an exception if the socket is blocking.
* _fatal_error() method of _UnixReadPipeTransport and _UnixWritePipeTransport
  now log all exceptions in debug mode
* Don't log expected errors in unit tests
* Tulip issue 200: _WaitHandleFuture._unregister_wait() now catchs and logs
  exceptions.
* Tulip issue 200: Log errors in debug mode instead of simply ignoring them.

* PipeServer.close() now cancels the "accept pipe" future which cancels the
  overlapped operation.
* Fix _SelectorTransport.__repr__() if the transport was closed
* Fix debug log in BaseEventLoop.create_connection(): get the socket object
  from the transport because SSL transport closes the old socket and creates a
  new SSL socket object. Remove also the _SelectorSslTransport._rawsock
  attribute: it contained the closed socket (not very useful) and it was not
  used.
* Issue #22063: socket operations (sock_recv, sock_sendall, sock_connect,
  sock_accept) of the proactor event loop don't raise an exception in debug
  mode if the socket are in blocking mode. Overlapped operations also work on
  blocking sockets.
* Fix unit tests in debug mode: mock a non-blocking socket for socket
  operations which now raise an exception if the socket is blocking.
* _fatal_error() method of _UnixReadPipeTransport and _UnixWritePipeTransport
  now log all exceptions in debug mode
* Don't log expected errors in unit tests
* Tulip issue 200: _WaitHandleFuture._unregister_wait() now catchs and logs
  exceptions.
* Tulip issue 200: Log errors in debug mode instead of simply ignoring them.

* dev: mention that the logging must be configured at DEBUG level
* streams: drain() has no more a strange return value, it's just
  a standard coroutine

* dev: mention that the logging must be configured at DEBUG level
* streams: drain() has no more a strange return value, it's just
  a standard coroutine

Patch by Daniel Shahaf.

posixpath.join().