Source code: Lib/asyncio/exceptions.py

exception asyncio.TimeoutError#

The operation has exceeded the given deadline.


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.

Changed in version 3.8: CancelledError is now a subclass of BaseException.

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.


The total number (int) of expected bytes.


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.


The total number of to be consumed bytes.