# Iterator Protocol

There are two functions specifically for working with iterators.

int PyIter_Check(PyObject *o)
  Part of the Stable ABI since version 3.8.

  Return non-zero if the object o can be safely passed to `PyIter_NextItem()` and `0` otherwise. This function always succeeds.

int PyAIter_Check(PyObject *o)
  Part of the Stable ABI since version 3.10.

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

  Added in version 3.10.

int PyIter_NextItem(PyObject *iter, PyObject **item)
  Part of the Stable ABI since version 3.14.

  Return `1` and set item to a 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.

  Added in version 3.14.

PyObject *PyIter_Next(PyObject *o)
  Return value: New reference. Part of the Stable ABI.

  This is an older version of `PyIter_NextItem()`, which is retained for backwards compatibility. Prefer `PyIter_NextItem()`.

  Return the next value from the iterator o. The object must be an iterator according to `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.

type PySendResult

  The enum value used to represent different results of `PyIter_Send()`.

  Added in version 3.10.

PySendResult PyIter_Send(PyObject *iter, PyObject *arg, PyObject **presult)
  Part of the Stable ABI since version 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`.

  Added in version 3.10.