Document the returned value.

Author: serhiy-storchaka

Doc/c-api/arg.rst

@@ -321,7 +321,10 @@ Other objects
    the conversion has failed.  When the conversion fails, the *converter* function
    should raise an exception and leave the content of *address* unmodified.
 
-   If the *converter* returns ``Py_CLEANUP_SUPPORTED``, it may get called a
+   .. c:macro:: Py_CLEANUP_SUPPORTED
+      :no-typesetting:
+
+   If the *converter* returns :c:macro:`!Py_CLEANUP_SUPPORTED`, it may get called a
    second time if the argument parsing eventually fails, giving the converter a
    chance to release any memory that it had already allocated. In this second
    call, the *object* parameter will be ``NULL``; *address* will have the same value
@@ -331,7 +334,7 @@ Other objects
    :c:func:`PyUnicode_FSDecoder`.
 
    .. versionchanged:: 3.1
-      ``Py_CLEANUP_SUPPORTED`` was added.
+      :c:macro:`!Py_CLEANUP_SUPPORTED` was added.
 
 ``p`` (:class:`bool`) [int]
    Tests the value passed in for truth (a boolean **p**\ redicate) and converts

Doc/c-api/unicode.rst

@@ -796,13 +796,15 @@ conversion function:
    :c:func:`PyUnicode_EncodeFSDefault`; :class:`bytes` objects are output as-is.
    *result* must be an address of a C variable of type :c:expr:`PyObject*`
    (or :c:expr:`PyBytesObject*`).
-   The variable is set to a new :term:`strong reference` to
+   On success, set the variable to a new :term:`strong reference` to
    a :ref:`bytes object <bytesobjects>` which must be released
-   when it is no longer used.
+   when it is no longer used and return non-zero value
+   (:c:macro:`Py_CLEANUP_SUPPORTED`).
    Embedded null bytes are not allowed in the result.
+   On failure, return ``0`` with an exception set.
 
    If *obj* is ``NULL``, the function releases a strong reference
-   stored in the variable referred by *result*.
+   stored in the variable referred by *result* and returns ``1``.
 
    .. versionadded:: 3.1
 
@@ -821,13 +823,15 @@ conversion function:
    objects are output as-is.
    *result* must be an address of a C variable of type :c:expr:`PyObject*`
    (or :c:expr:`PyUnicodeObject*`).
-   The variable is set to a new :term:`strong reference` to
+   On success, set the variable to a new :term:`strong reference` to
    a :ref:`Unicode object <unicodeobjects>` which must be released
-   when it is no longer used.
+   when it is no longer used and return non-zero value
+   (:c:macro:`Py_CLEANUP_SUPPORTED`).
    Embedded null characters are not allowed in the result.
+   On failure, return ``0`` with an exception set.
 
    If *obj* is ``NULL``, the function releases a strong reference
-   stored in the variable referred by *result*.
+   stored in the variable referred by *result* and returns ``1``.
 
    .. versionadded:: 3.2