[3.12] gh-102468: Document PyCFunction_New* and PyCMethod_New (GH-112557) (GH-114119)

gh-102468: Document `PyCFunction_New*` and `PyCMethod_New` (GH-112557)
(cherry picked from commit a482bc67ee)

Co-authored-by: AN Long <aisk@users.noreply.github.com>
Co-authored-by: Erlend E. Aasland <erlend.aasland@protonmail.com>

Doc/c-api/structures.rst

@@ -399,6 +399,40 @@ definition with the same method name.
    slot.  This is helpful because calls to PyCFunctions are optimized more
    than wrapper object calls.
 
+.. c:function:: PyObject * PyCMethod_New(PyMethodDef *ml, PyObject *self, PyObject *module, PyTypeObject *cls)
+
+   Turn *ml* into a Python :term:`callable` object.
+   The caller must ensure that *ml* outlives the :term:`callable`.
+   Typically, *ml* is defined as a static variable.
+
+   The *self* parameter will be passed as the *self* argument
+   to the C function in ``ml->ml_meth`` when invoked.
+   *self* can be ``NULL``.
+
+   The :term:`callable` object's ``__module__`` attribute
+   can be set from the given *module* argument.
+   *module* should be a Python string,
+   which will be used as name of the module the function is defined in.
+   If unavailable, it can be set to :const:`None` or ``NULL``.
+
+   .. seealso:: :attr:`function.__module__`
+
+   The *cls* parameter will be passed as the *defining_class*
+   argument to the C function.
+   Must be set if :c:macro:`METH_METHOD` is set on ``ml->ml_flags``.
+
+   .. versionadded:: 3.9
+
+
+.. c:function:: PyObject * PyCFunction_NewEx(PyMethodDef *ml, PyObject *self, PyObject *module)
+
+   Equivalent to ``PyCMethod_New(ml, self, module, NULL)``.
+
+
+.. c:function:: PyObject * PyCFunction_New(PyMethodDef *ml, PyObject *self)
+
+   Equivalent to ``PyCMethod_New(ml, self, NULL, NULL)``.
+
 
 Accessing attributes of extension types
 ---------------------------------------

Doc/data/refcounts.dat

@@ -402,6 +402,21 @@ PyContextVar_Reset:int:::
 PyContextVar_Reset:PyObject*:var:0:
 PyContextVar_Reset:PyObject*:token:-1:
 
+PyCFunction_New:PyObject*::+1:
+PyCFunction_New:PyMethodDef*:ml::
+PyCFunction_New:PyObject*:self:+1:
+
+PyCFunction_NewEx:PyObject*::+1:
+PyCFunction_NewEx:PyMethodDef*:ml::
+PyCFunction_NewEx:PyObject*:self:+1:
+PyCFunction_NewEx:PyObject*:module:+1:
+
+PyCMethod_New:PyObject*::+1:
+PyCMethod_New:PyMethodDef*:ml::
+PyCMethod_New:PyObject*:self:+1:
+PyCMethod_New:PyObject*:module:+1:
+PyCMethod_New:PyObject*:cls:+1:
+
 PyDate_Check:int:::
 PyDate_Check:PyObject*:ob:0: