List Objects
************

type PyListObject

   This subtype of "PyObject" represents a Python list object.

PyTypeObject PyList_Type
    * Part of the Stable ABI.*

   This instance of "PyTypeObject" represents the Python list type.
   This is the same object as "list" in the Python layer.

int PyList_Check(PyObject *p)
    * Thread safety: Atomic.*

   Return true if *p* is a list object or an instance of a subtype of
   the list type.  This function always succeeds.

int PyList_CheckExact(PyObject *p)
    * Thread safety: Atomic.*

   Return true if *p* is a list object, but not an instance of a
   subtype of the list type.  This function always succeeds.

PyObject *PyList_New(Py_ssize_t len)
    *Return value: New reference.** Part of the Stable ABI.** Thread
   safety: Atomic.*

   Return a new list of length *len* on success, or "NULL" on failure.

   Note:

     If *len* is greater than zero, the returned list object's items
     are set to "NULL". Thus you cannot use abstract API functions
     such as "PySequence_SetItem()" or expose the object to Python
     code before setting all items to a real object with
     "PyList_SetItem()" or "PyList_SET_ITEM()". The following APIs are
     safe APIs before the list is fully initialized:
     "PyList_SetItem()" and "PyList_SET_ITEM()".

Py_ssize_t PyList_Size(PyObject *list)
    * Part of the Stable ABI.** Thread safety: Atomic.*

   Return the length of the list object in *list*; this is equivalent
   to "len(list)" on a list object.

Py_ssize_t PyList_GET_SIZE(PyObject *list)
    * Thread safety: Atomic.*

   Similar to "PyList_Size()", but without error checking.

PyObject *PyList_GetItemRef(PyObject *list, Py_ssize_t index)
    *Return value: New reference.** Part of the Stable ABI since
   version 3.13.** Thread safety: Atomic.*

   Return the object at position *index* in the list pointed to by
   *list*.  The position must be non-negative; indexing from the end
   of the list is not supported.  If *index* is out of bounds ("<0 or
   >=len(list)"), return "NULL" and set an "IndexError" exception.

   Added in version 3.13.

PyObject *PyList_GetItem(PyObject *list, Py_ssize_t index)
    *Return value: Borrowed reference.** Part of the Stable ABI.**
   Thread safety: Safe to call from multiple threads with external
   synchronization only.*

   Like "PyList_GetItemRef()", but returns a *borrowed reference*
   instead of a *strong reference*.

   Note:

     In the *free-threaded build*, the returned *borrowed reference*
     may become invalid if another thread modifies the list
     concurrently. Prefer "PyList_GetItemRef()", which returns a
     *strong reference*.

PyObject *PyList_GET_ITEM(PyObject *list, Py_ssize_t i)
    *Return value: Borrowed reference.** Thread safety: Safe to call
   from multiple threads with external synchronization only.*

   Similar to "PyList_GetItem()", but without error checking.

   Note:

     In the *free-threaded build*, the returned *borrowed reference*
     may become invalid if another thread modifies the list
     concurrently. Prefer "PyList_GetItemRef()", which returns a
     *strong reference*.

int PyList_SetItem(PyObject *list, Py_ssize_t index, PyObject *item)
    * Part of the Stable ABI.** Thread safety: Atomic.*

   Set the item at index *index* in list to *item*.  Return "0" on
   success. If *index* is out of bounds, return "-1" and set an
   "IndexError" exception.

   Note:

     This function "steals" a reference to *item* and discards a
     reference to an item already in the list at the affected
     position.

void PyList_SET_ITEM(PyObject *list, Py_ssize_t i, PyObject *o)
    * Thread safety: Safe to call from multiple threads with external
   synchronization only.*

   Macro form of "PyList_SetItem()" without error checking. This is
   normally only used to fill in new lists where there is no previous
   content.

   Bounds checking is performed as an assertion if Python is built in
   debug mode or "with assertions".

   Note:

     This macro "steals" a reference to *item*, and, unlike
     "PyList_SetItem()", does *not* discard a reference to any item
     that is being replaced; any reference in *list* at position *i*
     will be leaked.

   Note:

     In the *free-threaded build*, this macro has no internal
     synchronization. It is normally only used to fill in new lists
     where no other thread has a reference to the list. If the list
     may be shared, use "PyList_SetItem()" instead, which uses a *per-
     object lock*.

int PyList_Insert(PyObject *list, Py_ssize_t index, PyObject *item)
    * Part of the Stable ABI.** Thread safety: Safe for concurrent use
   on the same object.*

   Insert the item *item* into list *list* in front of index *index*.
   Return "0" if successful; return "-1" and set an exception if
   unsuccessful. Analogous to "list.insert(index, item)".

int PyList_Append(PyObject *list, PyObject *item)
    * Part of the Stable ABI.** Thread safety: Atomic.*

   Append the object *item* at the end of list *list*. Return "0" if
   successful; return "-1" and set an exception if unsuccessful.
   Analogous to "list.append(item)".

PyObject *PyList_GetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high)
    *Return value: New reference.** Part of the Stable ABI.** Thread
   safety: Atomic.*

   Return a list of the objects in *list* containing the objects
   *between* *low* and *high*.  Return "NULL" and set an exception if
   unsuccessful.  Analogous to "list[low:high]".  Indexing from the
   end of the list is not supported.

int PyList_SetSlice(PyObject *list, Py_ssize_t low, Py_ssize_t high, PyObject *itemlist)
    * Part of the Stable ABI.** Thread safety: Safe for concurrent use
   on the same object.*

   Set the slice of *list* between *low* and *high* to the contents of
   *itemlist*.  Analogous to "list[low:high] = itemlist". The
   *itemlist* may be "NULL", indicating the assignment of an empty
   list (slice deletion). Return "0" on success, "-1" on failure.
   Indexing from the end of the list is not supported.

   Note:

     In the *free-threaded build*, when *itemlist* is a "list", both
     *list* and *itemlist* are locked for the duration of the
     operation. For other iterables (or "NULL"), only *list* is
     locked.

int PyList_Extend(PyObject *list, PyObject *iterable)
    * Thread safety: Safe for concurrent use on the same object.*

   Extend *list* with the contents of *iterable*.  This is the same as
   "PyList_SetSlice(list, PY_SSIZE_T_MAX, PY_SSIZE_T_MAX, iterable)"
   and analogous to "list.extend(iterable)" or "list += iterable".

   Raise an exception and return "-1" if *list* is not a "list"
   object. Return 0 on success.

   Added in version 3.13.

   Note:

     In the *free-threaded build*, when *iterable* is a "list", "set",
     "dict", or dict view, both *list* and *iterable* (or its
     underlying dict) are locked for the duration of the operation.
     For other iterables, only *list* is locked; *iterable* may be
     concurrently modified by another thread.

int PyList_Clear(PyObject *list)
    * Thread safety: Atomic.*

   Remove all items from *list*.  This is the same as
   "PyList_SetSlice(list, 0, PY_SSIZE_T_MAX, NULL)" and analogous to
   "list.clear()" or "del list[:]".

   Raise an exception and return "-1" if *list* is not a "list"
   object.  Return 0 on success.

   Added in version 3.13.

int PyList_Sort(PyObject *list)
    * Part of the Stable ABI.** Thread safety: Safe for concurrent use
   on the same object.*

   Sort the items of *list* in place.  Return "0" on success, "-1" on
   failure.  This is equivalent to "list.sort()".

   Note:

     In the *free-threaded build*, element comparison via "__lt__()"
     can execute arbitrary Python code, during which the *per-object
     lock* may be temporarily released. For built-in types ("str",
     "int", "float"), the lock is not released during comparison.

int PyList_Reverse(PyObject *list)
    * Part of the Stable ABI.** Thread safety: Safe for concurrent use
   on the same object.*

   Reverse the items of *list* in place.  Return "0" on success, "-1"
   on failure.  This is the equivalent of "list.reverse()".

PyObject *PyList_AsTuple(PyObject *list)
    *Return value: New reference.** Part of the Stable ABI.** Thread
   safety: Atomic.*

   Return a new tuple object containing the contents of *list*;
   equivalent to "tuple(list)".
