diff --git a/Doc/c-api/arg.rst b/Doc/c-api/arg.rst
index 158397a..29d3368 100644
--- a/Doc/c-api/arg.rst
+++ b/Doc/c-api/arg.rst
@@ -150,21 +150,11 @@
    any conversion.  Raises :exc:`TypeError` if the object is not a Unicode
    object.  The C variable may also be declared as :ctype:`PyObject\*`.
 
-``w`` (:class:`bytearray` or read-write character buffer) [char \*]
-   Similar to ``y``, but accepts any object which implements the read-write buffer
-   interface.  The caller must determine the length of the buffer by other means,
-   or use ``w#`` instead.  Only single-segment buffer objects are accepted;
-   :exc:`TypeError` is raised for all others.
-
 ``w*`` (:class:`bytearray` or read-write byte-oriented buffer) [Py_buffer]
-   This is to ``w`` what ``y*`` is to ``y``.
-
-``w#`` (:class:`bytearray` or read-write character buffer) [char \*, int]
-   Like ``y#``, but accepts any object which implements the read-write buffer
-   interface.  The :ctype:`char \*` variable is set to point to the first byte
-   of the buffer, and the :ctype:`int` is set to the length of the buffer.
-   Only single-segment buffer objects are accepted; :exc:`TypeError` is raised
-   for all others.
+   This format accepts any object which implements the read-write buffer
+   interface. It fills a :ctype:`Py_buffer` structure provided by the caller.
+   The buffer may contain embedded null bytes. The caller have to call
+   :cfunc:`PyBuffer_Release` when it is done with the buffer.
 
 ``es`` (:class:`str`) [const char \*encoding, char \*\*buffer]
    This variant on ``s`` is used for encoding Unicode into a character buffer.