python_doc_md/Advanced/c-api/iter.md

Iterator Protocol {#iterator}

There are two functions specifically for working with iterators.

Return non-zero if the object o can be safely passed to PyIter_NextItem{.interpreted-text role="c:func"} and 0 otherwise. This function always succeeds.

Return non-zero if the object o provides the AsyncIterator{.interpreted-text role="class"} protocol, and 0 otherwise. This function always succeeds.

::: versionadded 3.10 :::

Return 1 and set item to a strong reference{.interpreted-text role="term"} of the next value of the iterator iter on success. Return 0 and set item to NULL if there are no remaining values. Return -1, set item to NULL and set an exception on error.

::: versionadded 3.14 :::

This is an older version of !PyIter_NextItem{.interpreted-text role="c:func"}, which is retained for backwards compatibility. Prefer PyIter_NextItem{.interpreted-text role="c:func"}.

Return the next value from the iterator o. The object must be an iterator according to PyIter_Check{.interpreted-text role="c:func"} (it is up to the caller to check this). If there are no remaining values, returns NULL with no exception set. If an error occurs while retrieving the item, returns NULL and passes along the exception.

The enum value used to represent different results of PyIter_Send{.interpreted-text role="c:func"}.

::: versionadded 3.10 :::

Sends the arg value into the iterator iter. Returns:

• PYGEN_RETURN if iterator returns. Return value is returned via presult.
• PYGEN_NEXT if iterator yields. Yielded value is returned via presult.
• PYGEN_ERROR if iterator has raised an exception. presult is set to NULL.

::: versionadded 3.10 :::