Frame Objects — Python 3.13.12 documentation
Description: The PyEval_GetFrame() and PyThreadState_GetFrame() functions can be used to get a frame object. See also Reflection. Frame Locals Proxies: The f_locals attribute on a frame object is an instance of...

# Frame Objects

type PyFrameObject
  Part of the Limited API (as an opaque struct).

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

  There are no public members in this structure.

  Changed in version 3.11: The members of this structure were removed from the public C API. Refer to the What’s New entry for details.

The `PyEval_GetFrame()` and `PyThreadState_GetFrame()` functions can be used to get a frame object.

See also Reflection.

PyTypeObject PyFrame_Type

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

  Changed in version 3.11: Previously, this type was only available after including `<frameobject.h>`.

PyFrameObject *PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals, PyObject *locals)

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

int PyFrame_Check(PyObject *obj)

  Return non-zero if obj is a frame object.

  Changed in version 3.11: Previously, this function was only available after including `<frameobject.h>`.

PyFrameObject *PyFrame_GetBack(PyFrameObject *frame)
  Return value: New reference.

  Get the frame next outer frame.

  Return a strong reference, or `NULL` if frame has no outer frame.

  Added in version 3.9.

PyObject *PyFrame_GetBuiltins(PyFrameObject *frame)
  Return value: New reference.

  Get the frame’s `f_builtins` attribute.

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

  Added in version 3.11.

PyCodeObject *PyFrame_GetCode(PyFrameObject *frame)
  Return value: New reference. Part of the Stable ABI since version 3.10.

  Get the frame code.

  Return a strong reference.

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

  Added in version 3.9.

PyObject *PyFrame_GetGenerator(PyFrameObject *frame)
  Return value: New reference.

  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 strong reference, or `NULL`.

  Added in version 3.11.

PyObject *PyFrame_GetGlobals(PyFrameObject *frame)
  Return value: New reference.

  Get the frame’s `f_globals` attribute.

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

  Added in version 3.11.

int PyFrame_GetLasti(PyFrameObject *frame)

  Get the frame’s `f_lasti` attribute.

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

  Added in version 3.11.

PyObject *PyFrame_GetVar(PyFrameObject *frame, PyObject *name)
  Return value: New reference.

  Get the variable name of frame.

  - Return a strong reference to the variable value on success.

  - Raise `NameError` and return `NULL` if the variable does not exist.

  - Raise an exception and return `NULL` on error.

  name type must be a `str`.

  Added in version 3.12.

PyObject *PyFrame_GetVarString(PyFrameObject *frame, const char *name)
  Return value: New reference.

  Similar to `PyFrame_GetVar()`, but the variable name is a C string encoded in UTF-8.

  Added in version 3.12.

PyObject *PyFrame_GetLocals(PyFrameObject *frame)
  Return value: New reference.

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

  Return a strong reference.

  Added in version 3.11.

  Changed in version 3.13: As part of PEP 667, return an instance of `PyFrameLocalsProxy_Type`.

int PyFrame_GetLineNumber(PyFrameObject *frame)
  Part of the Stable ABI since version 3.10.

  Return the line number that frame is currently executing.

## Frame Locals Proxies

Added in version 3.13.

The `f_locals` attribute on a frame object 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.

PyTypeObject PyFrameLocalsProxy_Type

  The type of frame `locals()` proxy objects.

int PyFrameLocalsProxy_Check(PyObject *obj)

  Return non-zero if obj is a frame `locals()` proxy.

## Legacy Local Variable APIs

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

void PyFrame_LocalsToFast(PyFrameObject *f, int clear)

  This function is soft deprecated and does nothing.

  Prior to Python 3.13, this function would copy the `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.

  Changed in version 3.13: This function now does nothing.

void PyFrame_FastToLocals(PyFrameObject *f)

  This function is soft deprecated and does nothing.

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

  Changed in version 3.13: This function now does nothing.

int PyFrame_FastToLocalsWithError(PyFrameObject *f)

  This function is soft deprecated and does nothing.

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

  Changed in version 3.13: This function now does nothing.

See also

PEP 667

## Internal Frames

Unless using PEP 523, you will not need this.

struct _PyInterpreterFrame

  The interpreter’s internal frame representation.

  Added in version 3.11.

PyObject *PyUnstable_InterpreterFrame_GetCode(struct _PyInterpreterFrame *frame);
  This is Unstable API. It may change without warning in minor releases.

  > Return a strong reference to the code object for the frame.

  Added in version 3.12.

int PyUnstable_InterpreterFrame_GetLasti(struct _PyInterpreterFrame *frame);
  This is Unstable API. It may change without warning in minor releases.

  Return the byte offset into the last executed instruction.

  Added in version 3.12.

int PyUnstable_InterpreterFrame_GetLine(struct _PyInterpreterFrame *frame);
  This is Unstable API. It may change without warning in minor releases.

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

  Added in version 3.12.