# 函式物件 (Function Objects)

這有一些特用於 Python 函式的函式。

type PyFunctionObject

  用於函式的 C 結構。

PyTypeObject PyFunction_Type

  這是個 `PyTypeObject` 的實例，且代表了 Python 函式型別，Python 程式設計者可透過 `types.FunctionType` 使用它。

int PyFunction_Check(PyObject *o)

  如果 o 是個函式物件（擁有 `PyFunction_Type` 的型別）則回傳 true。參數必須不為 `NULL`。此函式必能成功執行。

PyObject *PyFunction_New(PyObject *code, PyObject *globals)
  回傳值：新的參照。

  回傳一個與程式碼物件 code 相關聯的函式物件。globals 必須是一個帶有函式能夠存取的全域變數的字典。

  函式的文件字串 (docstring) 和名稱是從程式碼物件所取得，`__module__` 是自 globals 所取得。引數預設值、標註 (annotation) 和閉包 (closure) 被設為 `NULL`，`__qualname__` 被設為和程式碼物件 `co_qualname` 欄位相同的值。

PyObject *PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname)
  回傳值：新的參照。

  和 `PyFunction_New()` 相似，但也允許函式物件 `__qualname__` 屬性的設定，qualname 應為一個 unicode 物件或是 `NULL`；如為 `NULL`，`__qualname__` 屬性會被設為與程式碼物件 `co_qualname` 欄位相同的值。

  在 3.3 版被加入.

PyObject *PyFunction_GetCode(PyObject *op)
  回傳值：借用參照。

  回傳與程式碼物件相關的函式物件 op。

PyObject *PyFunction_GetGlobals(PyObject *op)
  回傳值：借用參照。

  回傳與全域函式字典相關的函式物件 op。

PyObject *PyFunction_GetModule(PyObject *op)
  回傳值：借用參照。

  回傳一個函式物件 op 之 `__module__` 屬性的 borrowed reference，它可以是 NULL。

  這通常是個包含模組名稱的`字串`，但可以被 Python 程式設為任何其他物件。

PyObject *PyFunction_GetDefaults(PyObject *op)
  回傳值：借用參照。

  回傳函式物件 op 的引數預設值，這可以是一個含有多個引數的 tuple（元組）或 `NULL`。

int PyFunction_SetDefaults(PyObject *op, PyObject *defaults)

  設定函式物件 op 的引數預設值。defaults 必須是 `Py_None` 或一個 tuple。

  引發 `SystemError` 且在失敗時回傳 `-1`。

void PyFunction_SetVectorcall(PyFunctionObject *func, vectorcallfunc vectorcall)

  為一個給定的函式物件 func 設定 vectorcall 欄位。

  Warning: extensions using this API must preserve the behavior of the unaltered (default) vectorcall function!

  在 3.12 版被加入.

PyObject *PyFunction_GetClosure(PyObject *op)
  回傳值：借用參照。

  回傳與函式物件 op 相關聯的閉包，這可以是個 `NULL` 或是一個包含 cell 物件的 tuple。

int PyFunction_SetClosure(PyObject *op, PyObject *closure)

  設定與函式物件 op 相關聯的閉包，closure 必須是 `Py_None` 或是一個包含 cell 物件的 tuple。

  引發 `SystemError` 且在失敗時回傳 `-1`。

PyObject *PyFunction_GetAnnotations(PyObject *op)
  回傳值：借用參照。

  回傳函式物件 op 的標註，這可以是一個可變動的 (mutable) 字典或 `NULL`。

int PyFunction_SetAnnotations(PyObject *op, PyObject *annotations)

  設定函式物件 op 的標註，annotations 必須是一個字典或 `Py_None`。

  引發 `SystemError` 且在失敗時回傳 `-1`。

int PyFunction_AddWatcher(PyFunction_WatchCallback callback)

  Register callback as a function watcher for the current interpreter. Return an ID which may be passed to `PyFunction_ClearWatcher()`. In case of error (e.g. no more watcher IDs available), return `-1` and set an exception.

  在 3.12 版被加入.

int PyFunction_ClearWatcher(int watcher_id)

  Clear watcher identified by watcher_id previously returned from `PyFunction_AddWatcher()` for the current interpreter. Return `0` on success, or `-1` and set an exception on error (e.g. if the given watcher_id was never registered.)

  在 3.12 版被加入.

type PyFunction_WatchEvent

  > Enumeration of possible function watcher events:

  > - `PyFunction_EVENT_CREATE`

  > - `PyFunction_EVENT_DESTROY`

  > - `PyFunction_EVENT_MODIFY_CODE`

  > - `PyFunction_EVENT_MODIFY_DEFAULTS`

  > - `PyFunction_EVENT_MODIFY_KWDEFAULTS`

  在 3.12 版被加入.

typedef int (*PyFunction_WatchCallback)(PyFunction_WatchEvent event, PyFunctionObject *func, PyObject *new_value)

  Type of a function watcher callback function.

  If event is `PyFunction_EVENT_CREATE` or `PyFunction_EVENT_DESTROY` then new_value will be `NULL`. Otherwise, new_value will hold a borrowed reference to the new value that is about to be stored in func for the attribute that is being modified.

  The callback may inspect but must not modify func; doing so could have unpredictable effects, including infinite recursion.

  If event is `PyFunction_EVENT_CREATE`, then the callback is invoked after func has been fully initialized. Otherwise, the callback is invoked before the modification to func takes place, so the prior state of func can be inspected. The runtime is permitted to optimize away the creation of function objects when possible. In such cases no event will be emitted. Although this creates the possibility of an observable difference of runtime behavior depending on optimization decisions, it does not change the semantics of the Python code being executed.

  If event is `PyFunction_EVENT_DESTROY`, Taking a reference in the callback to the about-to-be-destroyed function will resurrect it, preventing it from being freed at this time. When the resurrected object is destroyed later, any watcher callbacks active at that time will be called again.

  If the callback sets an exception, it must return `-1`; this exception will be printed as an unraisable exception using `PyErr_WriteUnraisable()`. Otherwise it should return `0`.

  There may already be a pending exception set on entry to the callback. In this case, the callback should return `0` with the same exception still set. This means the callback may not call any other API that can set an exception unless it saves and clears the exception state first, and restores it before returning.

  在 3.12 版被加入.