python_doc_md/Intermediate/library/asyncio-exceptions.md

::: currentmodule asyncio :::

Exceptions {#asyncio-exceptions}

Source code: Lib/asyncio/exceptions.py{.interpreted-text role="source"}

---

:::: exception TimeoutError

A deprecated alias of TimeoutError{.interpreted-text role="exc"}, raised when the operation has exceeded the given deadline.

::: versionchanged 3.11

This class was made an alias of TimeoutError{.interpreted-text role="exc"}. ::: ::::

:::: 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

CancelledError{.interpreted-text role="exc"} is now a subclass of BaseException{.interpreted-text role="class"} rather than Exception{.interpreted-text role="class"}. ::: ::::

::: exception InvalidStateError

Invalid internal state of Task{.interpreted-text role="class"} or Future{.interpreted-text role="class"}.

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 RuntimeError{.interpreted-text role="exc"}. :::

::::: exception IncompleteReadError

The requested read operation did not complete fully.

Raised by the asyncio stream APIs<asyncio-streams>{.interpreted-text role="ref"}.

This exception is a subclass of EOFError{.interpreted-text role="exc"}.

::: attribute expected

The total number (int{.interpreted-text role="class"}) of expected bytes. :::

::: attribute partial

A string of bytes{.interpreted-text role="class"} read before the end of stream was reached. ::: :::::

:::: exception LimitOverrunError

Reached the buffer size limit while looking for a separator.

Raised by the asyncio stream APIs <asyncio-streams>{.interpreted-text role="ref"}.

::: attribute consumed

The total number of to be consumed bytes. ::: ::::