descriptor.html 22 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343
  1. <!DOCTYPE html>
  2. <html>
  3. <head>
  4. <meta charset="utf-8" />
  5. <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" />
  6. <meta property="og:title" content="Descriptor Objects" />
  7. <meta property="og:type" content="website" />
  8. <meta property="og:url" content="https://docs.python.org/3/c-api/descriptor.html" />
  9. <meta property="og:site_name" content="Python documentation" />
  10. <meta property="og:description" content="“Descriptors” are objects that describe some attribute of an object. They are found in the dictionary of type objects." />
  11. <meta property="og:image" content="https://docs.python.org/3/_static/og-image.png" />
  12. <meta property="og:image:alt" content="Python documentation" />
  13. <meta name="description" content="“Descriptors” are objects that describe some attribute of an object. They are found in the dictionary of type objects." />
  14. <meta property="og:image:width" content="200" />
  15. <meta property="og:image:height" content="200" />
  16. <meta name="theme-color" content="#3776ab" />
  17. <title>Descriptor Objects &#8212; Python 3.12.0 documentation</title><meta name="viewport" content="width=device-width, initial-scale=1.0">
  18. <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
  19. <link rel="stylesheet" type="text/css" href="../_static/pydoctheme.css?digest=b37c26da2f7529d09fe70b41c4b2133fe4931a90" />
  20. <link id="pygments_dark_css" media="(prefers-color-scheme: dark)" rel="stylesheet" type="text/css" href="../_static/pygments_dark.css" />
  21. <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
  22. <script src="../_static/jquery.js"></script>
  23. <script src="../_static/underscore.js"></script>
  24. <script src="../_static/doctools.js"></script>
  25. <script src="../_static/sidebar.js"></script>
  26. <link rel="search" type="application/opensearchdescription+xml"
  27. title="Search within Python 3.12.0 documentation"
  28. href="../_static/opensearch.xml"/>
  29. <link rel="author" title="About these documents" href="../about.html" />
  30. <link rel="index" title="Index" href="../genindex.html" />
  31. <link rel="search" title="Search" href="../search.html" />
  32. <link rel="copyright" title="Copyright" href="../copyright.html" />
  33. <link rel="next" title="Slice Objects" href="slice.html" />
  34. <link rel="prev" title="Iterator Objects" href="iterator.html" />
  35. <link rel="canonical" href="https://docs.python.org/3/c-api/descriptor.html" />
  36. <style>
  37. @media only screen {
  38. table.full-width-table {
  39. width: 100%;
  40. }
  41. }
  42. </style>
  43. <link rel="stylesheet" href="../_static/pydoctheme_dark.css" media="(prefers-color-scheme: dark)" id="pydoctheme_dark_css">
  44. <link rel="shortcut icon" type="image/png" href="../_static/py.svg" />
  45. <script type="text/javascript" src="../_static/copybutton.js"></script>
  46. <script type="text/javascript" src="../_static/menu.js"></script>
  47. <script type="text/javascript" src="../_static/themetoggle.js"></script>
  48. </head>
  49. <body>
  50. <div class="mobile-nav">
  51. <input type="checkbox" id="menuToggler" class="toggler__input" aria-controls="navigation"
  52. aria-pressed="false" aria-expanded="false" role="button" aria-label="Menu" />
  53. <nav class="nav-content" role="navigation">
  54. <label for="menuToggler" class="toggler__label">
  55. <span></span>
  56. </label>
  57. <span class="nav-items-wrapper">
  58. <a href="https://www.python.org/" class="nav-logo">
  59. <img src="../_static/py.svg" alt="Logo"/>
  60. </a>
  61. <span class="version_switcher_placeholder"></span>
  62. <form role="search" class="search" action="../search.html" method="get">
  63. <svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" class="search-icon">
  64. <path fill-rule="nonzero" fill="currentColor" d="M15.5 14h-.79l-.28-.27a6.5 6.5 0 001.48-5.34c-.47-2.78-2.79-5-5.59-5.34a6.505 6.505 0 00-7.27 7.27c.34 2.8 2.56 5.12 5.34 5.59a6.5 6.5 0 005.34-1.48l.27.28v.79l4.25 4.25c.41.41 1.08.41 1.49 0 .41-.41.41-1.08 0-1.49L15.5 14zm-6 0C7.01 14 5 11.99 5 9.5S7.01 5 9.5 5 14 7.01 14 9.5 11.99 14 9.5 14z"></path>
  65. </svg>
  66. <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
  67. <input type="submit" value="Go"/>
  68. </form>
  69. </span>
  70. </nav>
  71. <div class="menu-wrapper">
  72. <nav class="menu" role="navigation" aria-label="main navigation">
  73. <div class="language_switcher_placeholder"></div>
  74. <label class="theme-selector-label">
  75. Theme
  76. <select class="theme-selector" oninput="activateTheme(this.value)">
  77. <option value="auto" selected>Auto</option>
  78. <option value="light">Light</option>
  79. <option value="dark">Dark</option>
  80. </select>
  81. </label>
  82. <div>
  83. <h4>Previous topic</h4>
  84. <p class="topless"><a href="iterator.html"
  85. title="previous chapter">Iterator Objects</a></p>
  86. </div>
  87. <div>
  88. <h4>Next topic</h4>
  89. <p class="topless"><a href="slice.html"
  90. title="next chapter">Slice Objects</a></p>
  91. </div>
  92. <div role="note" aria-label="source link">
  93. <h3>This Page</h3>
  94. <ul class="this-page-menu">
  95. <li><a href="../bugs.html">Report a Bug</a></li>
  96. <li>
  97. <a href="https://github.com/python/cpython/blob/main/Doc/c-api/descriptor.rst"
  98. rel="nofollow">Show Source
  99. </a>
  100. </li>
  101. </ul>
  102. </div>
  103. </nav>
  104. </div>
  105. </div>
  106. <div class="related" role="navigation" aria-label="related navigation">
  107. <h3>Navigation</h3>
  108. <ul>
  109. <li class="right" style="margin-right: 10px">
  110. <a href="../genindex.html" title="General Index"
  111. accesskey="I">index</a></li>
  112. <li class="right" >
  113. <a href="../py-modindex.html" title="Python Module Index"
  114. >modules</a> |</li>
  115. <li class="right" >
  116. <a href="slice.html" title="Slice Objects"
  117. accesskey="N">next</a> |</li>
  118. <li class="right" >
  119. <a href="iterator.html" title="Iterator Objects"
  120. accesskey="P">previous</a> |</li>
  121. <li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
  122. <li><a href="https://www.python.org/">Python</a> &#187;</li>
  123. <li class="switchers">
  124. <div class="language_switcher_placeholder"></div>
  125. <div class="version_switcher_placeholder"></div>
  126. </li>
  127. <li>
  128. </li>
  129. <li id="cpython-language-and-version">
  130. <a href="../index.html">3.12.0 Documentation</a> &#187;
  131. </li>
  132. <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> &#187;</li>
  133. <li class="nav-item nav-item-2"><a href="concrete.html" accesskey="U">Concrete Objects Layer</a> &#187;</li>
  134. <li class="nav-item nav-item-this"><a href="">Descriptor Objects</a></li>
  135. <li class="right">
  136. <div class="inline-search" role="search">
  137. <form class="inline-search" action="../search.html" method="get">
  138. <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
  139. <input type="submit" value="Go" />
  140. </form>
  141. </div>
  142. |
  143. </li>
  144. <li class="right">
  145. <label class="theme-selector-label">
  146. Theme
  147. <select class="theme-selector" oninput="activateTheme(this.value)">
  148. <option value="auto" selected>Auto</option>
  149. <option value="light">Light</option>
  150. <option value="dark">Dark</option>
  151. </select>
  152. </label> |</li>
  153. </ul>
  154. </div>
  155. <div class="document">
  156. <div class="documentwrapper">
  157. <div class="bodywrapper">
  158. <div class="body" role="main">
  159. <section id="descriptor-objects">
  160. <span id="id1"></span><h1>Descriptor Objects<a class="headerlink" href="#descriptor-objects" title="Permalink to this headline">¶</a></h1>
  161. <p>“Descriptors” are objects that describe some attribute of an object. They are
  162. found in the dictionary of type objects.</p>
  163. <dl class="c var">
  164. <dt class="sig sig-object c" id="c.PyProperty_Type">
  165. <a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyProperty_Type</span></span></span><a class="headerlink" href="#c.PyProperty_Type" title="Permalink to this definition">¶</a><br /></dt>
  166. <dd><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em><p>The type object for the built-in descriptor types.</p>
  167. </dd></dl>
  168. <dl class="c function">
  169. <dt class="sig sig-object c" id="c.PyDescr_NewGetSet">
  170. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_NewGetSet</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">type</span></span>, <span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="structures.html#c.PyGetSetDef" title="PyGetSetDef"><span class="n"><span class="pre">PyGetSetDef</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">getset</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_NewGetSet" title="Permalink to this definition">¶</a><br /></dt>
  171. <dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em></dd></dl>
  172. <dl class="c function">
  173. <dt class="sig sig-object c" id="c.PyDescr_NewMember">
  174. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_NewMember</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">type</span></span>, <span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="structures.html#c.PyMemberDef" title="PyMemberDef"><span class="n"><span class="pre">PyMemberDef</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">meth</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_NewMember" title="Permalink to this definition">¶</a><br /></dt>
  175. <dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em></dd></dl>
  176. <dl class="c function">
  177. <dt class="sig sig-object c" id="c.PyDescr_NewMethod">
  178. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_NewMethod</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">type</span></span>, <span class="k"><span class="pre">struct</span></span><span class="w"> </span><a class="reference internal" href="structures.html#c.PyMethodDef" title="PyMethodDef"><span class="n"><span class="pre">PyMethodDef</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">meth</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_NewMethod" title="Permalink to this definition">¶</a><br /></dt>
  179. <dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em></dd></dl>
  180. <dl class="c function">
  181. <dt class="sig sig-object c" id="c.PyDescr_NewWrapper">
  182. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_NewWrapper</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">type</span></span>, <span class="k"><span class="pre">struct</span></span><span class="w"> </span><span class="n"><span class="pre">wrapperbase</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">wrapper</span></span>, <span class="kt"><span class="pre">void</span></span><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">wrapped</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_NewWrapper" title="Permalink to this definition">¶</a><br /></dt>
  183. <dd><em class="refcount">Return value: New reference.</em></dd></dl>
  184. <dl class="c function">
  185. <dt class="sig sig-object c" id="c.PyDescr_NewClassMethod">
  186. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_NewClassMethod</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="type.html#c.PyTypeObject" title="PyTypeObject"><span class="n"><span class="pre">PyTypeObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">type</span></span>, <a class="reference internal" href="structures.html#c.PyMethodDef" title="PyMethodDef"><span class="n"><span class="pre">PyMethodDef</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">method</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_NewClassMethod" title="Permalink to this definition">¶</a><br /></dt>
  187. <dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em></dd></dl>
  188. <dl class="c function">
  189. <dt class="sig sig-object c" id="c.PyDescr_IsData">
  190. <span class="kt"><span class="pre">int</span></span><span class="w"> </span><span class="sig-name descname"><span class="n"><span class="pre">PyDescr_IsData</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="n"><span class="pre">descr</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyDescr_IsData" title="Permalink to this definition">¶</a><br /></dt>
  191. <dd><p>Return non-zero if the descriptor objects <em>descr</em> describes a data attribute, or
  192. <code class="docutils literal notranslate"><span class="pre">0</span></code> if it describes a method. <em>descr</em> must be a descriptor object; there is
  193. no error checking.</p>
  194. </dd></dl>
  195. <dl class="c function">
  196. <dt class="sig sig-object c" id="c.PyWrapper_New">
  197. <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="w"> </span><span class="p"><span class="pre">*</span></span><span class="sig-name descname"><span class="n"><span class="pre">PyWrapper_New</span></span></span><span class="sig-paren">(</span><a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="p"><span class="pre">*</span></span>, <a class="reference internal" href="structures.html#c.PyObject" title="PyObject"><span class="n"><span class="pre">PyObject</span></span></a><span class="p"><span class="pre">*</span></span><span class="sig-paren">)</span><a class="headerlink" href="#c.PyWrapper_New" title="Permalink to this definition">¶</a><br /></dt>
  198. <dd><em class="refcount">Return value: New reference.</em><em class="stableabi"> Part of the <a class="reference internal" href="stable.html#stable"><span class="std std-ref">Stable ABI</span></a>.</em></dd></dl>
  199. </section>
  200. <div class="clearer"></div>
  201. </div>
  202. </div>
  203. </div>
  204. <div class="sphinxsidebar" role="navigation" aria-label="main navigation">
  205. <div class="sphinxsidebarwrapper">
  206. <div>
  207. <h4>Previous topic</h4>
  208. <p class="topless"><a href="iterator.html"
  209. title="previous chapter">Iterator Objects</a></p>
  210. </div>
  211. <div>
  212. <h4>Next topic</h4>
  213. <p class="topless"><a href="slice.html"
  214. title="next chapter">Slice Objects</a></p>
  215. </div>
  216. <div role="note" aria-label="source link">
  217. <h3>This Page</h3>
  218. <ul class="this-page-menu">
  219. <li><a href="../bugs.html">Report a Bug</a></li>
  220. <li>
  221. <a href="https://github.com/python/cpython/blob/main/Doc/c-api/descriptor.rst"
  222. rel="nofollow">Show Source
  223. </a>
  224. </li>
  225. </ul>
  226. </div>
  227. </div>
  228. </div>
  229. <div class="clearer"></div>
  230. </div>
  231. <div class="related" role="navigation" aria-label="related navigation">
  232. <h3>Navigation</h3>
  233. <ul>
  234. <li class="right" style="margin-right: 10px">
  235. <a href="../genindex.html" title="General Index"
  236. >index</a></li>
  237. <li class="right" >
  238. <a href="../py-modindex.html" title="Python Module Index"
  239. >modules</a> |</li>
  240. <li class="right" >
  241. <a href="slice.html" title="Slice Objects"
  242. >next</a> |</li>
  243. <li class="right" >
  244. <a href="iterator.html" title="Iterator Objects"
  245. >previous</a> |</li>
  246. <li><img src="../_static/py.svg" alt="python logo" style="vertical-align: middle; margin-top: -1px"/></li>
  247. <li><a href="https://www.python.org/">Python</a> &#187;</li>
  248. <li class="switchers">
  249. <div class="language_switcher_placeholder"></div>
  250. <div class="version_switcher_placeholder"></div>
  251. </li>
  252. <li>
  253. </li>
  254. <li id="cpython-language-and-version">
  255. <a href="../index.html">3.12.0 Documentation</a> &#187;
  256. </li>
  257. <li class="nav-item nav-item-1"><a href="index.html" >Python/C API Reference Manual</a> &#187;</li>
  258. <li class="nav-item nav-item-2"><a href="concrete.html" >Concrete Objects Layer</a> &#187;</li>
  259. <li class="nav-item nav-item-this"><a href="">Descriptor Objects</a></li>
  260. <li class="right">
  261. <div class="inline-search" role="search">
  262. <form class="inline-search" action="../search.html" method="get">
  263. <input placeholder="Quick search" aria-label="Quick search" type="search" name="q" />
  264. <input type="submit" value="Go" />
  265. </form>
  266. </div>
  267. |
  268. </li>
  269. <li class="right">
  270. <label class="theme-selector-label">
  271. Theme
  272. <select class="theme-selector" oninput="activateTheme(this.value)">
  273. <option value="auto" selected>Auto</option>
  274. <option value="light">Light</option>
  275. <option value="dark">Dark</option>
  276. </select>
  277. </label> |</li>
  278. </ul>
  279. </div>
  280. <div class="footer">
  281. &copy; <a href="../copyright.html">Copyright</a> 2001-2023, Python Software Foundation.
  282. <br />
  283. This page is licensed under the Python Software Foundation License Version 2.
  284. <br />
  285. Examples, recipes, and other code in the documentation are additionally licensed under the Zero Clause BSD License.
  286. <br />
  287. See <a href="/license.html">History and License</a> for more information.<br />
  288. <br />
  289. The Python Software Foundation is a non-profit corporation.
  290. <a href="https://www.python.org/psf/donations/">Please donate.</a>
  291. <br />
  292. <br />
  293. Last updated on Oct 02, 2023.
  294. <a href="/bugs.html">Found a bug</a>?
  295. <br />
  296. Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.5.0.
  297. </div>
  298. </body>
  299. </html>