Iterator Protocol

There are two functions specifically for working with iterators.

.. c:function:: int PyIter_Check(PyObject *o)

Return non-zero if the object o can be safely passed to :c:func:PyIter_NextItem and 0 otherwise. This function always succeeds.

.. c:function:: int PyAIter_Check(PyObject *o)

Return non-zero if the object o provides the :class:AsyncIterator protocol, and 0 otherwise. This function always succeeds.

.. versionadded:: 3.10

.. c:function:: int PyIter_NextItem(PyObject *iter, PyObject **item)

Return 1 and set item to a :term:strong reference 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

.. c:function:: PyObject* PyIter_Next(PyObject *o)

This is an older version of :c:func:!PyIter_NextItem, which is retained for backwards compatibility. Prefer :c:func:PyIter_NextItem.

Return the next value from the iterator o. The object must be an iterator according to :c:func:PyIter_Check (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.

.. c:type:: PySendResult

The enum value used to represent different results of :c:func:PyIter_Send.

.. versionadded:: 3.10

.. c:function:: PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)

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