.. currentmodule:: asyncio

.. _asyncio-exceptions:

========== Exceptions

Source code: :source:Lib/asyncio/exceptions.py

.. exception:: TimeoutError

A deprecated alias of :exc:TimeoutError, raised when the operation has exceeded the given deadline.

.. versionchanged:: 3.11

  This class was made an alias of :exc:`TimeoutError`.

.. exception:: CancelledError

The operation has been cancelled.

This exception can be caught to perform custom operations when asyncio Tasks are cancelled. In almost all situations the exception must be re-raised.

.. versionchanged:: 3.8

  :exc:`CancelledError` is now a subclass of :class:`BaseException` rather than :class:`Exception`.

.. exception:: InvalidStateError

Invalid internal state of :class:Task or :class:Future.

Can be raised in situations like setting a result value for a Future object that already has a result value set.

.. exception:: SendfileNotAvailableError

The "sendfile" syscall is not available for the given socket or file type.

A subclass of :exc:RuntimeError.

.. exception:: IncompleteReadError

The requested read operation did not complete fully.

Raised by the :ref:asyncio stream APIs<asyncio-streams>.

This exception is a subclass of :exc:EOFError.

.. attribute:: expected

  The total number (:class:`int`) of expected bytes.

.. attribute:: partial

  A string of :class:`bytes` read before the end of stream was reached.

.. exception:: LimitOverrunError

Reached the buffer size limit while looking for a separator.

Raised by the :ref:asyncio stream APIs <asyncio-streams>.

.. attribute:: consumed

  The total number of to be consumed bytes.