Closing #17378: ctypes documentation fix.
Document that ctypes automatically applies byref() when argtypes declares
POINTER.
diff --git a/Doc/library/ctypes.rst b/Doc/library/ctypes.rst
index b51ea51..7f62e30 100644
--- a/Doc/library/ctypes.rst
+++ b/Doc/library/ctypes.rst
@@ -816,6 +816,11 @@
3
>>>
+In addition, if a function argument is explicitly declared to be a pointer type
+(such as ``POINTER(c_int)``) in :attr:`argtypes`, an object of the pointed
+type (``c_int`` in this case) can be passed to the function. ctypes will apply
+the required :func:`byref` conversion in this case automatically.
+
To set a POINTER type field to ``NULL``, you can assign ``None``::
>>> bar.values = None