# Exceptions

exception `asyncio.``TimeoutError`

  The operation has exceeded the given deadline.

  Important

  This exception is different from the builtin `TimeoutError` exception.

exception `asyncio.``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.

  Important

  This exception is a subclass of `Exception`, so it can be accidentally suppressed by an overly broad `try..except` block:

      try:
          await operation
      except Exception:
          # The cancellation is broken because the *except* block
          # suppresses the CancelledError exception.
          log.log('an error has occurred')

  Instead, the following pattern should be used:

      try:
          await operation
      except asyncio.CancelledError:
          raise
      except Exception:
          log.log('an error has occurred')

exception `asyncio.``InvalidStateError`

  Invalid internal state of `Task` or `Future`.

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

exception `asyncio.``SendfileNotAvailableError`

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

  A subclass of `RuntimeError`.

exception `asyncio.``IncompleteReadError`

  The requested read operation did not complete fully.

  Raised by the asyncio stream APIs.

  This exception is a subclass of `EOFError`.

  `expected`

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

  `partial`

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

exception `asyncio.``LimitOverrunError`

  Reached the buffer size limit while looking for a separator.

  Raised by the asyncio stream APIs.

  `consumed`

    The total number of to be consumed bytes.