Add docs.

Author: ZeroIntensity

Doc/library/ctypes.rst

@@ -3161,6 +3161,72 @@ fields, or any other data types containing pointer type fields.
       that should be merged into a containing structure or union.
 
 
+.. decorator:: struct(*, align=None, layout, endian='native', pack=None)
+   :module: ctypes.util
+
+   A :term:`decorator` that allows generating structure types using an
+   annotation-based syntax, similar to the :mod:`dataclasses` module.
+
+   For example:
+
+   .. code-block:: python
+
+      from ctypes.util import struct
+      from ctypes import c_int
+
+      @struct
+      class Point:
+          x: c_int
+          y: c_int
+
+      point = Point(1, 2)
+
+   *align*, *layout*, and *pack* supply the value for the :attr:`~ctypes.Structure._align_`,
+   :attr:`~ctypes.Structure._layout_`, and :attr:`~ctypes.Structure._pack_`
+   attributes, respectively.
+
+   *endian* controls which structure class will be used as the base.
+
+   - If *endian* is ``'native'``, :class:`~ctypes.Structure` will be used.
+   - If *endian* is ``'big'``, :class:`~ctypes.BigEndianStructure` will be used.
+   - If *endian* is ``'little'``, :class:`~ctypes.LittleEndianStructure` will be used.
+
+   Any other value will raise a :class:`ValueError`.
+
+   For controlling field-specific data, wrap the annotation in :class:`typing.Annotated`
+   with :class:`CFieldInfo` as the second argument, like so:
+
+   .. code-block:: python
+
+      @struct
+      class PyObject:
+         ob_refcnt: c_ssize_t
+         ob_type: c_void_p
+
+      @struct
+      class PyHovercraftObject:
+         ob_base: Annotated[PyObject, CFieldInfo(anonymous=True)]
+
+   .. versionadded:: next
+
+
+.. class:: CFieldInfo(anonymous=False, bit_width=None)
+   :module: ctypes.util
+
+   Information regarding a structure field defined by the :func:`struct`
+   decorator. This should be used in the second argument of a
+   :class:`typing.Annotated` wrapping a ctypes type.
+
+   *anonymous* specifies whether the field will be present in the
+   :attr:`~Structure._anonymous_` attribute of the generated class.
+
+   If *bit_width* is non-``None``, the annotated field will be *bit_width*
+   number of bits in the generated structure. This is equivalent to passing
+   a third item in :attr:`~ctypes.Structure._fields_`.
+
+   .. versionadded:: next
+
+
 .. _ctypes-arrays-pointers:
 
 Arrays and pointers

Doc/whatsnew/3.16.rst

@@ -224,6 +224,16 @@ curses
   wide-character support.
   (Contributed by Serhiy Storchaka in :gh:`133031`.)
 
+
+ctypes
+------
+
+* Add :func:`ctypes.util.struct` for generating :class:`~ctypes.Structure` types
+  from an annotation-based syntax, similar to how the :mod:`dataclasses` module
+  is used.
+  (Contributed by Peter Bierma in :gh:`104533`.)
+
+
 encodings
 ---------
 

Lib/ctypes/util.py

@@ -565,6 +565,7 @@ class _Struct(_StructData, endian_class):
 
     _Struct.__name__ = klass.__name__
     _Struct.__qualname__ = klass.__qualname__
+    _Struct.__module__ = klass.__module__
     return _Struct