.. highlight:: c

Frame objects
-------------

.. c:type:: PyFrameObject

   The C structure of the objects used to describe frame objects.

   There are no public members in this structure.

   .. versionchanged:: 3.11
      The members of this structure were removed from the public C API.
      Refer to the :ref:`What's New entry <pyframeobject-3.11-hiding>`
      for details.

The :c:func:`PyEval_GetFrame` and :c:func:`PyThreadState_GetFrame` functions
can be used to get a frame object.

See also :ref:`Reflection <reflection>`.

.. c:var:: PyTypeObject PyFrame_Type

   The type of frame objects.
   It is the same object as :py:class:`types.FrameType` in the Python layer.

   .. versionchanged:: 3.11

      Previously, this type was only available after including
      ``<frameobject.h>``.

.. c:function:: PyFrameObject *PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals, PyObject *locals)

   Create a new frame object. This function returns a :term:`strong reference`
   to the new frame object on success, and returns ``NULL`` with an exception
   set on failure.

.. c:function:: int PyFrame_Check(PyObject *obj)

   Return non-zero if *obj* is a frame object.

   .. versionchanged:: 3.11

      Previously, this function was only available after including
      ``<frameobject.h>``.

.. c:function:: PyFrameObject* PyFrame_GetBack(PyFrameObject *frame)

   Get the *frame* next outer frame.

   Return a :term:`strong reference`, or ``NULL`` if *frame* has no outer
   frame.
   This raises no exceptions.

   .. versionadded:: 3.9


.. c:function:: PyObject* PyFrame_GetBuiltins(PyFrameObject *frame)

   Get the *frame*'s :attr:`~frame.f_builtins` attribute.

   Return a :term:`strong reference`. The result cannot be ``NULL``.

   .. versionadded:: 3.11


.. c:function:: PyCodeObject* PyFrame_GetCode(PyFrameObject *frame)

   Get the *frame* code.

   Return a :term:`strong reference`.

   The result (frame code) cannot be ``NULL``.

   .. versionadded:: 3.9


.. c:function:: PyObject* PyFrame_GetGenerator(PyFrameObject *frame)

   Get the generator, coroutine, or async generator that owns this frame,
   or ``NULL`` if this frame is not owned by a generator.
   Does not raise an exception, even if the return value is ``NULL``.

   Return a :term:`strong reference`, or ``NULL``.

   .. versionadded:: 3.11


.. c:function:: PyObject* PyFrame_GetGlobals(PyFrameObject *frame)

   Get the *frame*'s :attr:`~frame.f_globals` attribute.

   Return a :term:`strong reference`. The result cannot be ``NULL``.

   .. versionadded:: 3.11


.. c:function:: int PyFrame_GetLasti(PyFrameObject *frame)

   Get the *frame*'s :attr:`~frame.f_lasti` attribute.

   Returns -1 if ``frame.f_lasti`` is ``None``.

   .. versionadded:: 3.11


.. c:function:: PyObject* PyFrame_GetVar(PyFrameObject *frame, PyObject *name)

   Get the variable *name* of *frame*.

   * Return a :term:`strong reference` to the variable value on success.
   * Raise :exc:`NameError` and return ``NULL`` if the variable does not exist.
   * Raise an exception and return ``NULL`` on error.

   *name* type must be a :class:`str`.

   .. versionadded:: 3.12


.. c:function:: PyObject* PyFrame_GetVarString(PyFrameObject *frame, const char *name)

   Similar to :c:func:`PyFrame_GetVar`, but the variable name is a C string
   encoded in UTF-8.

   .. versionadded:: 3.12


.. c:function:: PyObject* PyFrame_GetLocals(PyFrameObject *frame)

   Get the *frame*'s :attr:`~frame.f_locals` attribute.
   If the frame refers to an :term:`optimized scope`, this returns a
   write-through proxy object that allows modifying the locals.
   In all other cases (classes, modules, :func:`exec`, :func:`eval`) it returns
   the mapping representing the frame locals directly (as described for
   :func:`locals`).

   Return a :term:`strong reference`.

   .. versionadded:: 3.11

   .. versionchanged:: 3.13
      As part of :pep:`667`, return an instance of :c:var:`PyFrameLocalsProxy_Type`.


.. c:function:: int PyFrame_GetLineNumber(PyFrameObject *frame)

   Return the line number that *frame* is currently executing.


Frame locals proxies
^^^^^^^^^^^^^^^^^^^^

.. versionadded:: 3.13

The :attr:`~frame.f_locals` attribute on a :ref:`frame object <frame-objects>`
is an instance of a "frame-locals proxy". The proxy object exposes a
write-through view of the underlying locals dictionary for the frame. This
ensures that the variables exposed by ``f_locals`` are always up to date with
the live local variables in the frame itself.

See :pep:`667` for more information.

.. c:var:: PyTypeObject PyFrameLocalsProxy_Type

   The type of frame :func:`locals` proxy objects.

.. c:function:: int PyFrameLocalsProxy_Check(PyObject *obj)

   Return non-zero if *obj* is a frame :func:`locals` proxy.


Legacy local variable APIs
^^^^^^^^^^^^^^^^^^^^^^^^^^

These APIs are :term:`soft deprecated`. As of Python 3.13, they do nothing.
They exist solely for backwards compatibility.


.. c:function:: void PyFrame_LocalsToFast(PyFrameObject *f, int clear)

   Prior to Python 3.13, this function would copy the :attr:`~frame.f_locals`
   attribute of *f* to the internal "fast" array of local variables, allowing
   changes in frame objects to be visible to the interpreter. If *clear* was
   true, this function would process variables that were unset in the locals
   dictionary.

   .. soft-deprecated:: 3.13
      This function now does nothing.


.. c:function:: void PyFrame_FastToLocals(PyFrameObject *f)

   Prior to Python 3.13, this function would copy the internal "fast" array
   of local variables (which is used by the interpreter) to the
   :attr:`~frame.f_locals` attribute of *f*, allowing changes in local
   variables to be visible to frame objects.

   .. soft-deprecated:: 3.13
      This function now does nothing.


.. c:function:: int PyFrame_FastToLocalsWithError(PyFrameObject *f)

   Prior to Python 3.13, this function was similar to
   :c:func:`PyFrame_FastToLocals`, but would return ``0`` on success, and
   ``-1`` with an exception set on failure.

   .. soft-deprecated:: 3.13
      This function now does nothing.


.. seealso::
   :pep:`667`


Internal frames
^^^^^^^^^^^^^^^

Unless using :pep:`523`, you will not need this.

.. c:struct:: _PyInterpreterFrame

   The interpreter's internal frame representation.

   .. versionadded:: 3.11

.. c:function:: PyObject* PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame);

    Return a :term:`strong reference` to the code object for the frame.

   .. versionadded:: 3.12


.. c:function:: int PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame);

   Return the byte offset into the last executed instruction.

   .. versionadded:: 3.12


.. c:function:: int PyUnstable_InterpreterFrame_GetLine(struct _PyInterpreterFrame *frame);

   Return the currently executing line number, or -1 if there is no line number.

   .. versionadded:: 3.12


.. c:var:: const PyTypeObject *PyUnstable_ExecutableKinds

   An array of executable kinds (executor types) for frames, used for internal
   debugging and tracing.

   Tools like debuggers and profilers can use this to identify the type of execution
   context associated with a frame (such as to filter out internal frames).
   The entries are indexed by the following constants:

   .. list-table::
      :header-rows: 1
      :widths: auto

      * - Constant
        - Description
      * - .. c:macro:: PyUnstable_EXECUTABLE_KIND_SKIP
        - The frame is internal (For example: inlined) and should be skipped by tools.
      * - .. c:macro:: PyUnstable_EXECUTABLE_KIND_PY_FUNCTION
        - The frame corresponds to a standard Python function.
      * - .. c:macro:: PyUnstable_EXECUTABLE_KIND_BUILTIN_FUNCTION
        - The frame corresponds to a function defined in native code.
      * - .. c:macro:: PyUnstable_EXECUTABLE_KIND_METHOD_DESCRIPTOR
        - The frame corresponds to a method on a class instance.

   Note that reading the executable kind from a frame is currently only
   possible with undocumented internal APIs.

   .. versionadded:: 3.13


.. c:macro:: PyUnstable_EXECUTABLE_KINDS

   The number of entries in :c:data:`PyUnstable_ExecutableKinds`.

   .. versionadded:: 3.13

