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  98. <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code> — Low-level networking interface</a><ul>

  99. <li><a class="reference internal" href="#socket-families">Socket families</a></li>

  100. <li><a class="reference internal" href="#module-contents">Module contents</a><ul>

  101. <li><a class="reference internal" href="#exceptions">Exceptions</a></li>

  102. <li><a class="reference internal" href="#constants">Constants</a></li>

  103. <li><a class="reference internal" href="#functions">Functions</a><ul>

  104. <li><a class="reference internal" href="#creating-sockets">Creating sockets</a></li>

  105. <li><a class="reference internal" href="#other-functions">Other functions</a></li>

  106. </ul>

  107. </li>

  108. </ul>

  109. </li>

  110. <li><a class="reference internal" href="#socket-objects">Socket Objects</a></li>

  111. <li><a class="reference internal" href="#notes-on-socket-timeouts">Notes on socket timeouts</a><ul>

  112. <li><a class="reference internal" href="#timeouts-and-the-connect-method">Timeouts and the <code class="docutils literal notranslate"><span class="pre">connect</span></code> method</a></li>

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  209.   <section id="module-socket">

  210. <span id="socket-low-level-networking-interface"></span><h1><a class="reference internal" href="#module-socket" title="socket: Low-level networking interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code></a> — Low-level networking interface<a class="headerlink" href="#module-socket" title="Link to this heading">¶</a></h1>

  211. <p><strong>Source code:</strong> <a class="reference external" href="https://github.com/python/cpython/tree/3.12/Lib/socket.py">Lib/socket.py</a></p>

  212. <hr class="docutils" />

  213. <p>This module provides access to the BSD <em>socket</em> interface. It is available on

  214. all modern Unix systems, Windows, MacOS, and probably additional platforms.</p>

  215. <div class="admonition note">

  216. <p class="admonition-title">Note</p>

  217. <p>Some behavior may be platform dependent, since calls are made to the operating

  218. system socket APIs.</p>

  219. </div>

  220. <div class="availability docutils container">

  221. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not Emscripten, not WASI.</p>

  222. <p>This module does not work or is not available on WebAssembly platforms

  223. <code class="docutils literal notranslate"><span class="pre">wasm32-emscripten</span></code> and <code class="docutils literal notranslate"><span class="pre">wasm32-wasi</span></code>. See

  224. <a class="reference internal" href="intro.html#wasm-availability"><span class="std std-ref">WebAssembly platforms</span></a> for more information.</p>

  225. </div>

  226. <p id="index-0">The Python interface is a straightforward transliteration of the Unix system

  227. call and library interface for sockets to Python’s object-oriented style: the

  228. <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a> function returns a <em class="dfn">socket object</em> whose methods implement

  229. the various socket system calls.  Parameter types are somewhat higher-level than

  230. in the C interface: as with <code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code> and <code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code> operations on Python

  231. files, buffer allocation on receive operations is automatic, and buffer length

  232. is implicit on send operations.</p>

  233. <div class="admonition seealso">

  234. <p class="admonition-title">See also</p>

  235. <dl class="simple">

  236. <dt>Module <a class="reference internal" href="socketserver.html#module-socketserver" title="socketserver: A framework for network servers."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socketserver</span></code></a></dt><dd><p>Classes that simplify writing network servers.</p>

  237. </dd>

  238. <dt>Module <a class="reference internal" href="ssl.html#module-ssl" title="ssl: TLS/SSL wrapper for socket objects"><code class="xref py py-mod docutils literal notranslate"><span class="pre">ssl</span></code></a></dt><dd><p>A TLS/SSL wrapper for socket objects.</p>

  239. </dd>

  240. </dl>

  241. </div>

  242. <section id="socket-families">

  243. <h2>Socket families<a class="headerlink" href="#socket-families" title="Link to this heading">¶</a></h2>

  244. <p>Depending on the system and the build options, various socket families

  245. are supported by this module.</p>

  246. <p>The address format required by a particular socket object is automatically

  247. selected based on the address family specified when the socket object was

  248. created.  Socket addresses are represented as follows:</p>

  249. <ul>

  250. <li><p>The address of an <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> socket bound to a file system node

  251. is represented as a string, using the file system encoding and the

  252. <code class="docutils literal notranslate"><span class="pre">'surrogateescape'</span></code> error handler (see <span class="target" id="index-1"></span><a class="pep reference external" href="https://peps.python.org/pep-0383/"><strong>PEP 383</strong></a>).  An address in

  253. Linux’s abstract namespace is returned as a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> with

  254. an initial null byte; note that sockets in this namespace can

  255. communicate with normal file system sockets, so programs intended to

  256. run on Linux may need to deal with both types of address.  A string or

  257. bytes-like object can be used for either type of address when

  258. passing it as an argument.</p>

  259. <div class="versionchanged">

  260. <p><span class="versionmodified changed">Changed in version 3.3: </span>Previously, <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> socket paths were assumed to use UTF-8

  261. encoding.</p>

  262. </div>

  263. <div class="versionchanged">

  264. <p><span class="versionmodified changed">Changed in version 3.5: </span>Writable <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> is now accepted.</p>

  265. </div>

  266. </li>

  267. </ul>

  268. <ul id="host-port">

  269. <li><p>A pair <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code> is used for the <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a> address family,

  270. where <em>host</em> is a string representing either a hostname in internet domain

  271. notation like <code class="docutils literal notranslate"><span class="pre">'daring.cwi.nl'</span></code> or an IPv4 address like <code class="docutils literal notranslate"><span class="pre">'100.50.200.5'</span></code>,

  272. and <em>port</em> is an integer.</p>

  273. <ul class="simple">

  274. <li><p>For IPv4 addresses, two special forms are accepted instead of a host

  275. address: <code class="docutils literal notranslate"><span class="pre">''</span></code> represents <code class="xref py py-const docutils literal notranslate"><span class="pre">INADDR_ANY</span></code>, which is used to bind to all

  276. interfaces, and the string <code class="docutils literal notranslate"><span class="pre">'&lt;broadcast&gt;'</span></code> represents

  277. <code class="xref py py-const docutils literal notranslate"><span class="pre">INADDR_BROADCAST</span></code>.  This behavior is not compatible with IPv6,

  278. therefore, you may want to avoid these if you intend to support IPv6 with your

  279. Python programs.</p></li>

  280. </ul>

  281. </li>

  282. <li><p>For <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET6</span></code></a> address family, a four-tuple <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port,</span> <span class="pre">flowinfo,</span>

  283. <span class="pre">scope_id)</span></code> is used, where <em>flowinfo</em> and <em>scope_id</em> represent the <code class="docutils literal notranslate"><span class="pre">sin6_flowinfo</span></code>

  284. and <code class="docutils literal notranslate"><span class="pre">sin6_scope_id</span></code> members in <code class="xref py py-const docutils literal notranslate"><span class="pre">struct</span> <span class="pre">sockaddr_in6</span></code> in C.  For

  285. <a class="reference internal" href="#module-socket" title="socket: Low-level networking interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code></a> module methods, <em>flowinfo</em> and <em>scope_id</em> can be omitted just for

  286. backward compatibility.  Note, however, omission of <em>scope_id</em> can cause problems

  287. in manipulating scoped IPv6 addresses.</p>

  288. <div class="versionchanged">

  289. <p><span class="versionmodified changed">Changed in version 3.7: </span>For multicast addresses (with <em>scope_id</em> meaningful) <em>address</em> may not contain

  290. <code class="docutils literal notranslate"><span class="pre">%scope_id</span></code> (or <code class="docutils literal notranslate"><span class="pre">zone</span> <span class="pre">id</span></code>) part. This information is superfluous and may

  291. be safely omitted (recommended).</p>

  292. </div>

  293. </li>

  294. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_NETLINK</span></code> sockets are represented as pairs <code class="docutils literal notranslate"><span class="pre">(pid,</span> <span class="pre">groups)</span></code>.</p></li>

  295. <li><p>Linux-only support for TIPC is available using the <code class="xref py py-const docutils literal notranslate"><span class="pre">AF_TIPC</span></code>

  296. address family.  TIPC is an open, non-IP based networked protocol designed

  297. for use in clustered computer environments.  Addresses are represented by a

  298. tuple, and the fields depend on the address type. The general tuple form is

  299. <code class="docutils literal notranslate"><span class="pre">(addr_type,</span> <span class="pre">v1,</span> <span class="pre">v2,</span> <span class="pre">v3</span> <span class="pre">[,</span> <span class="pre">scope])</span></code>, where:</p>

  300. <ul>

  301. <li><p><em>addr_type</em> is one of <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_NAMESEQ</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_NAME</span></code>,

  302. or <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_ID</span></code>.</p></li>

  303. <li><p><em>scope</em> is one of <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ZONE_SCOPE</span></code>, <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_CLUSTER_SCOPE</span></code>, and

  304. <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_NODE_SCOPE</span></code>.</p></li>

  305. <li><p>If <em>addr_type</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_NAME</span></code>, then <em>v1</em> is the server type, <em>v2</em> is

  306. the port identifier, and <em>v3</em> should be 0.</p>

  307. <p>If <em>addr_type</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_NAMESEQ</span></code>, then <em>v1</em> is the server type, <em>v2</em>

  308. is the lower port number, and <em>v3</em> is the upper port number.</p>

  309. <p>If <em>addr_type</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">TIPC_ADDR_ID</span></code>, then <em>v1</em> is the node, <em>v2</em> is the

  310. reference, and <em>v3</em> should be set to 0.</p>

  311. </li>

  312. </ul>

  313. </li>

  314. <li><p>A tuple <code class="docutils literal notranslate"><span class="pre">(interface,</span> <span class="pre">)</span></code> is used for the <a class="reference internal" href="#socket.AF_CAN" title="socket.AF_CAN"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_CAN</span></code></a> address family,

  315. where <em>interface</em> is a string representing a network interface name like

  316. <code class="docutils literal notranslate"><span class="pre">'can0'</span></code>. The network interface name <code class="docutils literal notranslate"><span class="pre">''</span></code> can be used to receive packets

  317. from all network interfaces of this family.</p>

  318. <ul class="simple">

  319. <li><p><a class="reference internal" href="#socket.CAN_ISOTP" title="socket.CAN_ISOTP"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_ISOTP</span></code></a> protocol require a tuple <code class="docutils literal notranslate"><span class="pre">(interface,</span> <span class="pre">rx_addr,</span> <span class="pre">tx_addr)</span></code>

  320. where both additional parameters are unsigned long integer that represent a

  321. CAN identifier (standard or extended).</p></li>

  322. <li><p><a class="reference internal" href="#socket.CAN_J1939" title="socket.CAN_J1939"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_J1939</span></code></a> protocol require a tuple <code class="docutils literal notranslate"><span class="pre">(interface,</span> <span class="pre">name,</span> <span class="pre">pgn,</span> <span class="pre">addr)</span></code>

  323. where additional parameters are 64-bit unsigned integer representing the

  324. ECU name, a 32-bit unsigned integer representing the Parameter Group Number

  325. (PGN), and an 8-bit integer representing the address.</p></li>

  326. </ul>

  327. </li>

  328. <li><p>A string or a tuple <code class="docutils literal notranslate"><span class="pre">(id,</span> <span class="pre">unit)</span></code> is used for the <code class="xref py py-const docutils literal notranslate"><span class="pre">SYSPROTO_CONTROL</span></code>

  329. protocol of the <code class="xref py py-const docutils literal notranslate"><span class="pre">PF_SYSTEM</span></code> family. The string is the name of a

  330. kernel control using a dynamically assigned ID. The tuple can be used if ID

  331. and unit number of the kernel control are known or if a registered ID is

  332. used.</p>

  333. <div class="versionadded">

  334. <p><span class="versionmodified added">New in version 3.3.</span></p>

  335. </div>

  336. </li>

  337. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_BLUETOOTH</span></code> supports the following protocols and address

  338. formats:</p>

  339. <ul>

  340. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_L2CAP</span></code> accepts <code class="docutils literal notranslate"><span class="pre">(bdaddr,</span> <span class="pre">psm)</span></code> where <code class="docutils literal notranslate"><span class="pre">bdaddr</span></code> is

  341. the Bluetooth address as a string and <code class="docutils literal notranslate"><span class="pre">psm</span></code> is an integer.</p></li>

  342. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_RFCOMM</span></code> accepts <code class="docutils literal notranslate"><span class="pre">(bdaddr,</span> <span class="pre">channel)</span></code> where <code class="docutils literal notranslate"><span class="pre">bdaddr</span></code>

  343. is the Bluetooth address as a string and <code class="docutils literal notranslate"><span class="pre">channel</span></code> is an integer.</p></li>

  344. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_HCI</span></code> accepts <code class="docutils literal notranslate"><span class="pre">(device_id,)</span></code> where <code class="docutils literal notranslate"><span class="pre">device_id</span></code> is

  345. either an integer or a string with the Bluetooth address of the

  346. interface. (This depends on your OS; NetBSD and DragonFlyBSD expect

  347. a Bluetooth address while everything else expects an integer.)</p>

  348. <div class="versionchanged">

  349. <p><span class="versionmodified changed">Changed in version 3.2: </span>NetBSD and DragonFlyBSD support added.</p>

  350. </div>

  351. </li>

  352. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_SCO</span></code> accepts <code class="docutils literal notranslate"><span class="pre">bdaddr</span></code> where <code class="docutils literal notranslate"><span class="pre">bdaddr</span></code> is a

  353. <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object containing the Bluetooth address in a

  354. string format. (ex. <code class="docutils literal notranslate"><span class="pre">b'12:23:34:45:56:67'</span></code>) This protocol is not

  355. supported under FreeBSD.</p></li>

  356. </ul>

  357. </li>

  358. <li><p><a class="reference internal" href="#socket.AF_ALG" title="socket.AF_ALG"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_ALG</span></code></a> is a Linux-only socket based interface to Kernel

  359. cryptography. An algorithm socket is configured with a tuple of two to four

  360. elements <code class="docutils literal notranslate"><span class="pre">(type,</span> <span class="pre">name</span> <span class="pre">[,</span> <span class="pre">feat</span> <span class="pre">[,</span> <span class="pre">mask]])</span></code>, where:</p>

  361. <ul class="simple">

  362. <li><p><em>type</em> is the algorithm type as string, e.g. <code class="docutils literal notranslate"><span class="pre">aead</span></code>, <code class="docutils literal notranslate"><span class="pre">hash</span></code>,

  363. <code class="docutils literal notranslate"><span class="pre">skcipher</span></code> or <code class="docutils literal notranslate"><span class="pre">rng</span></code>.</p></li>

  364. <li><p><em>name</em> is the algorithm name and operation mode as string, e.g.

  365. <code class="docutils literal notranslate"><span class="pre">sha256</span></code>, <code class="docutils literal notranslate"><span class="pre">hmac(sha256)</span></code>, <code class="docutils literal notranslate"><span class="pre">cbc(aes)</span></code> or <code class="docutils literal notranslate"><span class="pre">drbg_nopr_ctr_aes256</span></code>.</p></li>

  366. <li><p><em>feat</em> and <em>mask</em> are unsigned 32bit integers.</p></li>

  367. </ul>

  368. <div class="availability docutils container">

  369. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.38.</p>

  370. <p>Some algorithm types require more recent Kernels.</p>

  371. </div>

  372. <div class="versionadded">

  373. <p><span class="versionmodified added">New in version 3.6.</span></p>

  374. </div>

  375. </li>

  376. <li><p><a class="reference internal" href="#socket.AF_VSOCK" title="socket.AF_VSOCK"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_VSOCK</span></code></a> allows communication between virtual machines and

  377. their hosts. The sockets are represented as a <code class="docutils literal notranslate"><span class="pre">(CID,</span> <span class="pre">port)</span></code> tuple

  378. where the context ID or CID and port are integers.</p>

  379. <div class="availability docutils container">

  380. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 3.9</p>

  381. <p>See <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/vsock(7)">vsock(7)</a></em></p>

  382. </div>

  383. <div class="versionadded">

  384. <p><span class="versionmodified added">New in version 3.7.</span></p>

  385. </div>

  386. </li>

  387. <li><p><a class="reference internal" href="#socket.AF_PACKET" title="socket.AF_PACKET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_PACKET</span></code></a> is a low-level interface directly to network devices.

  388. The addresses are represented by the tuple

  389. <code class="docutils literal notranslate"><span class="pre">(ifname,</span> <span class="pre">proto[,</span> <span class="pre">pkttype[,</span> <span class="pre">hatype[,</span> <span class="pre">addr]]])</span></code> where:</p>

  390. <ul class="simple">

  391. <li><p><em>ifname</em> - String specifying the device name.</p></li>

  392. <li><p><em>proto</em> - The Ethernet protocol number.

  393. May be <a class="reference internal" href="#socket.ETH_P_ALL" title="socket.ETH_P_ALL"><code class="xref py py-data docutils literal notranslate"><span class="pre">ETH_P_ALL</span></code></a> to capture all protocols,

  394. one of the <a class="reference internal" href="#socket-ethernet-types"><span class="std std-ref">ETHERTYPE_* constants</span></a>

  395. or any other Ethernet protocol number.</p></li>

  396. <li><p><em>pkttype</em> - Optional integer specifying the packet type:</p>

  397. <ul>

  398. <li><p><code class="docutils literal notranslate"><span class="pre">PACKET_HOST</span></code> (the default) - Packet addressed to the local host.</p></li>

  399. <li><p><code class="docutils literal notranslate"><span class="pre">PACKET_BROADCAST</span></code> - Physical-layer broadcast packet.</p></li>

  400. <li><p><code class="docutils literal notranslate"><span class="pre">PACKET_MULTICAST</span></code> - Packet sent to a physical-layer multicast address.</p></li>

  401. <li><p><code class="docutils literal notranslate"><span class="pre">PACKET_OTHERHOST</span></code> - Packet to some other host that has been caught by

  402. a device driver in promiscuous mode.</p></li>

  403. <li><p><code class="docutils literal notranslate"><span class="pre">PACKET_OUTGOING</span></code> - Packet originating from the local host that is

  404. looped back to a packet socket.</p></li>

  405. </ul>

  406. </li>

  407. <li><p><em>hatype</em> - Optional integer specifying the ARP hardware address type.</p></li>

  408. <li><p><em>addr</em> - Optional bytes-like object specifying the hardware physical

  409. address, whose interpretation depends on the device.</p></li>

  410. </ul>

  411. <div class="availability docutils container">

  412. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.2.</p>

  413. </div>

  414. </li>

  415. <li><p><a class="reference internal" href="#socket.AF_QIPCRTR" title="socket.AF_QIPCRTR"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_QIPCRTR</span></code></a> is a Linux-only socket based interface for communicating

  416. with services running on co-processors in Qualcomm platforms. The address

  417. family is represented as a <code class="docutils literal notranslate"><span class="pre">(node,</span> <span class="pre">port)</span></code> tuple where the <em>node</em> and <em>port</em>

  418. are non-negative integers.</p>

  419. <div class="availability docutils container">

  420. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 4.7.</p>

  421. </div>

  422. <div class="versionadded">

  423. <p><span class="versionmodified added">New in version 3.8.</span></p>

  424. </div>

  425. </li>

  426. <li><p><code class="xref py py-const docutils literal notranslate"><span class="pre">IPPROTO_UDPLITE</span></code> is a variant of UDP which allows you to specify

  427. what portion of a packet is covered with the checksum. It adds two socket

  428. options that you can change.

  429. <code class="docutils literal notranslate"><span class="pre">self.setsockopt(IPPROTO_UDPLITE,</span> <span class="pre">UDPLITE_SEND_CSCOV,</span> <span class="pre">length)</span></code> will

  430. change what portion of outgoing packets are covered by the checksum and

  431. <code class="docutils literal notranslate"><span class="pre">self.setsockopt(IPPROTO_UDPLITE,</span> <span class="pre">UDPLITE_RECV_CSCOV,</span> <span class="pre">length)</span></code> will

  432. filter out packets which cover too little of their data. In both cases

  433. <code class="docutils literal notranslate"><span class="pre">length</span></code> should be in <code class="docutils literal notranslate"><span class="pre">range(8,</span> <span class="pre">2**16,</span> <span class="pre">8)</span></code>.</p>

  434. <p>Such a socket should be constructed with

  435. <code class="docutils literal notranslate"><span class="pre">socket(AF_INET,</span> <span class="pre">SOCK_DGRAM,</span> <span class="pre">IPPROTO_UDPLITE)</span></code> for IPv4 or

  436. <code class="docutils literal notranslate"><span class="pre">socket(AF_INET6,</span> <span class="pre">SOCK_DGRAM,</span> <span class="pre">IPPROTO_UDPLITE)</span></code> for IPv6.</p>

  437. <div class="availability docutils container">

  438. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.20, FreeBSD &gt;= 10.1</p>

  439. </div>

  440. <div class="versionadded">

  441. <p><span class="versionmodified added">New in version 3.9.</span></p>

  442. </div>

  443. </li>

  444. <li><p><a class="reference internal" href="#socket.AF_HYPERV" title="socket.AF_HYPERV"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_HYPERV</span></code></a> is a Windows-only socket based interface for communicating

  445. with Hyper-V hosts and guests. The address family is represented as a

  446. <code class="docutils literal notranslate"><span class="pre">(vm_id,</span> <span class="pre">service_id)</span></code> tuple where the <code class="docutils literal notranslate"><span class="pre">vm_id</span></code> and <code class="docutils literal notranslate"><span class="pre">service_id</span></code> are

  447. UUID strings.</p>

  448. <p>The <code class="docutils literal notranslate"><span class="pre">vm_id</span></code> is the virtual machine identifier or a set of known VMID values

  449. if the target is not a specific virtual machine. Known VMID constants

  450. defined on <code class="docutils literal notranslate"><span class="pre">socket</span></code> are:</p>

  451. <ul class="simple">

  452. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_ZERO</span></code></p></li>

  453. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_BROADCAST</span></code></p></li>

  454. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_WILDCARD</span></code> - Used to bind on itself and accept connections from

  455. all partitions.</p></li>

  456. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_CHILDREN</span></code> - Used to bind on itself and accept connection from

  457. child partitions.</p></li>

  458. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_LOOPBACK</span></code> - Used as a target to itself.</p></li>

  459. <li><p><code class="docutils literal notranslate"><span class="pre">HV_GUID_PARENT</span></code> - When used as a bind accepts connection from the parent

  460. partition. When used as an address target it will connect to the parent partition.</p></li>

  461. </ul>

  462. <p>The <code class="docutils literal notranslate"><span class="pre">service_id</span></code> is the service identifier of the registered service.</p>

  463. <div class="versionadded">

  464. <p><span class="versionmodified added">New in version 3.12.</span></p>

  465. </div>

  466. </li>

  467. </ul>

  468. <p>If you use a hostname in the <em>host</em> portion of IPv4/v6 socket address, the

  469. program may show a nondeterministic behavior, as Python uses the first address

  470. returned from the DNS resolution.  The socket address will be resolved

  471. differently into an actual IPv4/v6 address, depending on the results from DNS

  472. resolution and/or the host configuration.  For deterministic behavior use a

  473. numeric address in <em>host</em> portion.</p>

  474. <p>All errors raise exceptions.  The normal exceptions for invalid argument types

  475. and out-of-memory conditions can be raised. Errors

  476. related to socket or address semantics raise <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> or one of its

  477. subclasses.</p>

  478. <p>Non-blocking mode is supported through <a class="reference internal" href="#socket.socket.setblocking" title="socket.socket.setblocking"><code class="xref py py-meth docutils literal notranslate"><span class="pre">setblocking()</span></code></a>.  A

  479. generalization of this based on timeouts is supported through

  480. <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a>.</p>

  481. </section>

  482. <section id="module-contents">

  483. <h2>Module contents<a class="headerlink" href="#module-contents" title="Link to this heading">¶</a></h2>

  484. <p>The module <a class="reference internal" href="#module-socket" title="socket: Low-level networking interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code></a> exports the following elements.</p>

  485. <section id="exceptions">

  486. <h3>Exceptions<a class="headerlink" href="#exceptions" title="Link to this heading">¶</a></h3>

  487. <dl class="py exception">

  488. <dt class="sig sig-object py" id="socket.error">

  489. <em class="property"><span class="pre">exception</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">error</span></span><a class="headerlink" href="#socket.error" title="Link to this definition">¶</a></dt>

  490. <dd><p>A deprecated alias of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.</p>

  491. <div class="versionchanged">

  492. <p><span class="versionmodified changed">Changed in version 3.3: </span>Following <span class="target" id="index-2"></span><a class="pep reference external" href="https://peps.python.org/pep-3151/"><strong>PEP 3151</strong></a>, this class was made an alias of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.</p>

  493. </div>

  494. </dd></dl>

  495. 

  496. <dl class="py exception">

  497. <dt class="sig sig-object py" id="socket.herror">

  498. <em class="property"><span class="pre">exception</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">herror</span></span><a class="headerlink" href="#socket.herror" title="Link to this definition">¶</a></dt>

  499. <dd><p>A subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>, this exception is raised for

  500. address-related errors, i.e. for functions that use <em>h_errno</em> in the POSIX

  501. C API, including <a class="reference internal" href="#socket.gethostbyname_ex" title="socket.gethostbyname_ex"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyname_ex()</span></code></a> and <a class="reference internal" href="#socket.gethostbyaddr" title="socket.gethostbyaddr"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyaddr()</span></code></a>.

  502. The accompanying value is a pair <code class="docutils literal notranslate"><span class="pre">(h_errno,</span> <span class="pre">string)</span></code> representing an

  503. error returned by a library call.  <em>h_errno</em> is a numeric value, while

  504. <em>string</em> represents the description of <em>h_errno</em>, as returned by the

  505. <code class="xref c c-func docutils literal notranslate"><span class="pre">hstrerror()</span></code> C function.</p>

  506. <div class="versionchanged">

  507. <p><span class="versionmodified changed">Changed in version 3.3: </span>This class was made a subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.</p>

  508. </div>

  509. </dd></dl>

  510. 

  511. <dl class="py exception">

  512. <dt class="sig sig-object py" id="socket.gaierror">

  513. <em class="property"><span class="pre">exception</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gaierror</span></span><a class="headerlink" href="#socket.gaierror" title="Link to this definition">¶</a></dt>

  514. <dd><p>A subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>, this exception is raised for

  515. address-related errors by <a class="reference internal" href="#socket.getaddrinfo" title="socket.getaddrinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getaddrinfo()</span></code></a> and <a class="reference internal" href="#socket.getnameinfo" title="socket.getnameinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getnameinfo()</span></code></a>.

  516. The accompanying value is a pair <code class="docutils literal notranslate"><span class="pre">(error,</span> <span class="pre">string)</span></code> representing an error

  517. returned by a library call.  <em>string</em> represents the description of

  518. <em>error</em>, as returned by the <code class="xref c c-func docutils literal notranslate"><span class="pre">gai_strerror()</span></code> C function.  The

  519. numeric <em>error</em> value will match one of the <code class="xref py py-const docutils literal notranslate"><span class="pre">EAI_*</span></code> constants

  520. defined in this module.</p>

  521. <div class="versionchanged">

  522. <p><span class="versionmodified changed">Changed in version 3.3: </span>This class was made a subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.</p>

  523. </div>

  524. </dd></dl>

  525. 

  526. <dl class="py exception">

  527. <dt class="sig sig-object py" id="socket.timeout">

  528. <em class="property"><span class="pre">exception</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">timeout</span></span><a class="headerlink" href="#socket.timeout" title="Link to this definition">¶</a></dt>

  529. <dd><p>A deprecated alias of <a class="reference internal" href="exceptions.html#TimeoutError" title="TimeoutError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TimeoutError</span></code></a>.</p>

  530. <p>A subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>, this exception is raised when a timeout

  531. occurs on a socket which has had timeouts enabled via a prior call to

  532. <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a> (or implicitly through

  533. <a class="reference internal" href="#socket.setdefaulttimeout" title="socket.setdefaulttimeout"><code class="xref py py-func docutils literal notranslate"><span class="pre">setdefaulttimeout()</span></code></a>).  The accompanying value is a string

  534. whose value is currently always “timed out”.</p>

  535. <div class="versionchanged">

  536. <p><span class="versionmodified changed">Changed in version 3.3: </span>This class was made a subclass of <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a>.</p>

  537. </div>

  538. <div class="versionchanged">

  539. <p><span class="versionmodified changed">Changed in version 3.10: </span>This class was made an alias of <a class="reference internal" href="exceptions.html#TimeoutError" title="TimeoutError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TimeoutError</span></code></a>.</p>

  540. </div>

  541. </dd></dl>

  542. 

  543. </section>

  544. <section id="constants">

  545. <h3>Constants<a class="headerlink" href="#constants" title="Link to this heading">¶</a></h3>

  546. <blockquote>

  547. <div><p>The AF_* and SOCK_* constants are now <code class="xref py py-class docutils literal notranslate"><span class="pre">AddressFamily</span></code> and

  548. <code class="xref py py-class docutils literal notranslate"><span class="pre">SocketKind</span></code> <a class="reference internal" href="enum.html#enum.IntEnum" title="enum.IntEnum"><code class="xref py py-class docutils literal notranslate"><span class="pre">IntEnum</span></code></a> collections.</p>

  549. <div class="versionadded">

  550. <p><span class="versionmodified added">New in version 3.4.</span></p>

  551. </div>

  552. </div></blockquote>

  553. <dl class="py data">

  554. <dt class="sig sig-object py" id="socket.AF_UNIX">

  555. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_UNIX</span></span><a class="headerlink" href="#socket.AF_UNIX" title="Link to this definition">¶</a></dt>

  556. <dt class="sig sig-object py" id="socket.AF_INET">

  557. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_INET</span></span><a class="headerlink" href="#socket.AF_INET" title="Link to this definition">¶</a></dt>

  558. <dt class="sig sig-object py" id="socket.AF_INET6">

  559. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_INET6</span></span><a class="headerlink" href="#socket.AF_INET6" title="Link to this definition">¶</a></dt>

  560. <dd><p>These constants represent the address (and protocol) families, used for the

  561. first argument to <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a>.  If the <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> constant is not

  562. defined then this protocol is unsupported.  More constants may be available

  563. depending on the system.</p>

  564. </dd></dl>

  565. 

  566. <dl class="py data">

  567. <dt class="sig sig-object py" id="socket.AF_UNSPEC">

  568. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_UNSPEC</span></span><a class="headerlink" href="#socket.AF_UNSPEC" title="Link to this definition">¶</a></dt>

  569. <dd><p><a class="reference internal" href="#socket.AF_UNSPEC" title="socket.AF_UNSPEC"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNSPEC</span></code></a> means that

  570. <a class="reference internal" href="#socket.getaddrinfo" title="socket.getaddrinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getaddrinfo()</span></code></a> should return socket addresses for any

  571. address family (either IPv4, IPv6, or any other) that can be used.</p>

  572. </dd></dl>

  573. 

  574. <dl class="py data">

  575. <dt class="sig sig-object py" id="socket.SOCK_STREAM">

  576. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_STREAM</span></span><a class="headerlink" href="#socket.SOCK_STREAM" title="Link to this definition">¶</a></dt>

  577. <dt class="sig sig-object py" id="socket.SOCK_DGRAM">

  578. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_DGRAM</span></span><a class="headerlink" href="#socket.SOCK_DGRAM" title="Link to this definition">¶</a></dt>

  579. <dt class="sig sig-object py" id="socket.SOCK_RAW">

  580. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_RAW</span></span><a class="headerlink" href="#socket.SOCK_RAW" title="Link to this definition">¶</a></dt>

  581. <dt class="sig sig-object py" id="socket.SOCK_RDM">

  582. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_RDM</span></span><a class="headerlink" href="#socket.SOCK_RDM" title="Link to this definition">¶</a></dt>

  583. <dt class="sig sig-object py" id="socket.SOCK_SEQPACKET">

  584. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_SEQPACKET</span></span><a class="headerlink" href="#socket.SOCK_SEQPACKET" title="Link to this definition">¶</a></dt>

  585. <dd><p>These constants represent the socket types, used for the second argument to

  586. <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a>.  More constants may be available depending on the system.

  587. (Only <a class="reference internal" href="#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code></a> and <a class="reference internal" href="#socket.SOCK_DGRAM" title="socket.SOCK_DGRAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_DGRAM</span></code></a> appear to be generally

  588. useful.)</p>

  589. </dd></dl>

  590. 

  591. <dl class="py data">

  592. <dt class="sig sig-object py" id="socket.SOCK_CLOEXEC">

  593. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_CLOEXEC</span></span><a class="headerlink" href="#socket.SOCK_CLOEXEC" title="Link to this definition">¶</a></dt>

  594. <dt class="sig sig-object py" id="socket.SOCK_NONBLOCK">

  595. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOCK_NONBLOCK</span></span><a class="headerlink" href="#socket.SOCK_NONBLOCK" title="Link to this definition">¶</a></dt>

  596. <dd><p>These two constants, if defined, can be combined with the socket types and

  597. allow you to set some flags atomically (thus avoiding possible race

  598. conditions and the need for separate calls).</p>

  599. <div class="admonition seealso">

  600. <p class="admonition-title">See also</p>

  601. <p><a class="reference external" href="https://udrepper.livejournal.com/20407.html">Secure File Descriptor Handling</a>

  602. for a more thorough explanation.</p>

  603. </div>

  604. <div class="availability docutils container">

  605. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.27.</p>

  606. </div>

  607. <div class="versionadded">

  608. <p><span class="versionmodified added">New in version 3.2.</span></p>

  609. </div>

  610. </dd></dl>

  611. 

  612. <dl class="py data" id="socket-unix-constants">

  613. <dt class="sig sig-object py">

  614. <span class="sig-name descname"><span class="pre">SO_*</span></span></dt>

  615. <dt class="sig sig-object py" id="socket.SOMAXCONN">

  616. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOMAXCONN</span></span><a class="headerlink" href="#socket.SOMAXCONN" title="Link to this definition">¶</a></dt>

  617. <dt class="sig sig-object py">

  618. <span class="sig-name descname"><span class="pre">MSG_*</span></span></dt>

  619. <dt class="sig sig-object py">

  620. <span class="sig-name descname"><span class="pre">SOL_*</span></span></dt>

  621. <dt class="sig sig-object py">

  622. <span class="sig-name descname"><span class="pre">SCM_*</span></span></dt>

  623. <dt class="sig sig-object py">

  624. <span class="sig-name descname"><span class="pre">IPPROTO_*</span></span></dt>

  625. <dt class="sig sig-object py">

  626. <span class="sig-name descname"><span class="pre">IPPORT_*</span></span></dt>

  627. <dt class="sig sig-object py">

  628. <span class="sig-name descname"><span class="pre">INADDR_*</span></span></dt>

  629. <dt class="sig sig-object py">

  630. <span class="sig-name descname"><span class="pre">IP_*</span></span></dt>

  631. <dt class="sig sig-object py">

  632. <span class="sig-name descname"><span class="pre">IPV6_*</span></span></dt>

  633. <dt class="sig sig-object py">

  634. <span class="sig-name descname"><span class="pre">EAI_*</span></span></dt>

  635. <dt class="sig sig-object py">

  636. <span class="sig-name descname"><span class="pre">AI_*</span></span></dt>

  637. <dt class="sig sig-object py">

  638. <span class="sig-name descname"><span class="pre">NI_*</span></span></dt>

  639. <dt class="sig sig-object py">

  640. <span class="sig-name descname"><span class="pre">TCP_*</span></span></dt>

  641. <dd><p>Many constants of these forms, documented in the Unix documentation on sockets

  642. and/or the IP protocol, are also defined in the socket module. They are

  643. generally used in arguments to the <a class="reference internal" href="#socket.socket.setsockopt" title="socket.socket.setsockopt"><code class="xref py py-meth docutils literal notranslate"><span class="pre">setsockopt()</span></code></a> and <a class="reference internal" href="#socket.socket.getsockopt" title="socket.socket.getsockopt"><code class="xref py py-meth docutils literal notranslate"><span class="pre">getsockopt()</span></code></a>

  644. methods of socket objects.  In most cases, only those symbols that are defined

  645. in the Unix header files are defined; for a few symbols, default values are

  646. provided.</p>

  647. <div class="versionchanged">

  648. <p><span class="versionmodified changed">Changed in version 3.6: </span><code class="docutils literal notranslate"><span class="pre">SO_DOMAIN</span></code>, <code class="docutils literal notranslate"><span class="pre">SO_PROTOCOL</span></code>, <code class="docutils literal notranslate"><span class="pre">SO_PEERSEC</span></code>, <code class="docutils literal notranslate"><span class="pre">SO_PASSSEC</span></code>,

  649. <code class="docutils literal notranslate"><span class="pre">TCP_USER_TIMEOUT</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_CONGESTION</span></code> were added.</p>

  650. </div>

  651. <div class="versionchanged">

  652. <p><span class="versionmodified changed">Changed in version 3.6.5: </span>On Windows, <code class="docutils literal notranslate"><span class="pre">TCP_FASTOPEN</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_KEEPCNT</span></code> appear if run-time Windows

  653. supports.</p>

  654. </div>

  655. <div class="versionchanged">

  656. <p><span class="versionmodified changed">Changed in version 3.7: </span><code class="docutils literal notranslate"><span class="pre">TCP_NOTSENT_LOWAT</span></code> was added.</p>

  657. <p>On Windows, <code class="docutils literal notranslate"><span class="pre">TCP_KEEPIDLE</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_KEEPINTVL</span></code> appear if run-time Windows

  658. supports.</p>

  659. </div>

  660. <div class="versionchanged">

  661. <p><span class="versionmodified changed">Changed in version 3.10: </span><code class="docutils literal notranslate"><span class="pre">IP_RECVTOS</span></code> was added.

  662.  Added <code class="docutils literal notranslate"><span class="pre">TCP_KEEPALIVE</span></code>. On MacOS this constant can be used in the same

  663.  way that <code class="docutils literal notranslate"><span class="pre">TCP_KEEPIDLE</span></code> is used on Linux.</p>

  664. </div>

  665. <div class="versionchanged">

  666. <p><span class="versionmodified changed">Changed in version 3.11: </span>Added <code class="docutils literal notranslate"><span class="pre">TCP_CONNECTION_INFO</span></code>. On MacOS this constant can be used in the

  667. same way that <code class="docutils literal notranslate"><span class="pre">TCP_INFO</span></code> is used on Linux and BSD.</p>

  668. </div>

  669. <div class="versionchanged">

  670. <p><span class="versionmodified changed">Changed in version 3.12: </span>Added <code class="docutils literal notranslate"><span class="pre">SO_RTABLE</span></code> and <code class="docutils literal notranslate"><span class="pre">SO_USER_COOKIE</span></code>. On OpenBSD

  671. and FreeBSD respectively those constants can be used in the same way that

  672. <code class="docutils literal notranslate"><span class="pre">SO_MARK</span></code> is used on Linux. Also added missing TCP socket options from

  673. Linux: <code class="docutils literal notranslate"><span class="pre">TCP_MD5SIG</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_THIN_LINEAR_TIMEOUTS</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_THIN_DUPACK</span></code>,

  674. <code class="docutils literal notranslate"><span class="pre">TCP_REPAIR</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_REPAIR_QUEUE</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_QUEUE_SEQ</span></code>,

  675. <code class="docutils literal notranslate"><span class="pre">TCP_REPAIR_OPTIONS</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_TIMESTAMP</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_CC_INFO</span></code>,

  676. <code class="docutils literal notranslate"><span class="pre">TCP_SAVE_SYN</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_SAVED_SYN</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_REPAIR_WINDOW</span></code>,

  677. <code class="docutils literal notranslate"><span class="pre">TCP_FASTOPEN_CONNECT</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_ULP</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_MD5SIG_EXT</span></code>,

  678. <code class="docutils literal notranslate"><span class="pre">TCP_FASTOPEN_KEY</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_FASTOPEN_NO_COOKIE</span></code>,

  679. <code class="docutils literal notranslate"><span class="pre">TCP_ZEROCOPY_RECEIVE</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_INQ</span></code>, <code class="docutils literal notranslate"><span class="pre">TCP_TX_DELAY</span></code>.

  680. Added <code class="docutils literal notranslate"><span class="pre">IP_PKTINFO</span></code>, <code class="docutils literal notranslate"><span class="pre">IP_UNBLOCK_SOURCE</span></code>, <code class="docutils literal notranslate"><span class="pre">IP_BLOCK_SOURCE</span></code>,

  681. <code class="docutils literal notranslate"><span class="pre">IP_ADD_SOURCE_MEMBERSHIP</span></code>, <code class="docutils literal notranslate"><span class="pre">IP_DROP_SOURCE_MEMBERSHIP</span></code>.</p>

  682. </div>

  683. </dd></dl>

  684. 

  685. <dl class="py data">

  686. <dt class="sig sig-object py" id="socket.AF_CAN">

  687. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_CAN</span></span><a class="headerlink" href="#socket.AF_CAN" title="Link to this definition">¶</a></dt>

  688. <dt class="sig sig-object py" id="socket.PF_CAN">

  689. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">PF_CAN</span></span><a class="headerlink" href="#socket.PF_CAN" title="Link to this definition">¶</a></dt>

  690. <dt class="sig sig-object py">

  691. <span class="sig-name descname"><span class="pre">SOL_CAN_*</span></span></dt>

  692. <dt class="sig sig-object py">

  693. <span class="sig-name descname"><span class="pre">CAN_*</span></span></dt>

  694. <dd><p>Many constants of these forms, documented in the Linux documentation, are

  695. also defined in the socket module.</p>

  696. <div class="availability docutils container">

  697. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.25, NetBSD &gt;= 8.</p>

  698. </div>

  699. <div class="versionadded">

  700. <p><span class="versionmodified added">New in version 3.3.</span></p>

  701. </div>

  702. <div class="versionchanged">

  703. <p><span class="versionmodified changed">Changed in version 3.11: </span>NetBSD support was added.</p>

  704. </div>

  705. </dd></dl>

  706. 

  707. <dl class="py data">

  708. <dt class="sig sig-object py" id="socket.CAN_BCM">

  709. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CAN_BCM</span></span><a class="headerlink" href="#socket.CAN_BCM" title="Link to this definition">¶</a></dt>

  710. <dt class="sig sig-object py">

  711. <span class="sig-name descname"><span class="pre">CAN_BCM_*</span></span></dt>

  712. <dd><p>CAN_BCM, in the CAN protocol family, is the broadcast manager (BCM) protocol.

  713. Broadcast manager constants, documented in the Linux documentation, are also

  714. defined in the socket module.</p>

  715. <div class="availability docutils container">

  716. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.25.</p>

  717. </div>

  718. <div class="admonition note">

  719. <p class="admonition-title">Note</p>

  720. <p>The <code class="xref py py-data docutils literal notranslate"><span class="pre">CAN_BCM_CAN_FD_FRAME</span></code> flag is only available on Linux &gt;= 4.8.</p>

  721. </div>

  722. <div class="versionadded">

  723. <p><span class="versionmodified added">New in version 3.4.</span></p>

  724. </div>

  725. </dd></dl>

  726. 

  727. <dl class="py data">

  728. <dt class="sig sig-object py" id="socket.CAN_RAW_FD_FRAMES">

  729. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CAN_RAW_FD_FRAMES</span></span><a class="headerlink" href="#socket.CAN_RAW_FD_FRAMES" title="Link to this definition">¶</a></dt>

  730. <dd><p>Enables CAN FD support in a CAN_RAW socket. This is disabled by default.

  731. This allows your application to send both CAN and CAN FD frames; however,

  732. you must accept both CAN and CAN FD frames when reading from the socket.</p>

  733. <p>This constant is documented in the Linux documentation.</p>

  734. <div class="availability docutils container">

  735. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 3.6.</p>

  736. </div>

  737. <div class="versionadded">

  738. <p><span class="versionmodified added">New in version 3.5.</span></p>

  739. </div>

  740. </dd></dl>

  741. 

  742. <dl class="py data">

  743. <dt class="sig sig-object py" id="socket.CAN_RAW_JOIN_FILTERS">

  744. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CAN_RAW_JOIN_FILTERS</span></span><a class="headerlink" href="#socket.CAN_RAW_JOIN_FILTERS" title="Link to this definition">¶</a></dt>

  745. <dd><p>Joins the applied CAN filters such that only CAN frames that match all

  746. given CAN filters are passed to user space.</p>

  747. <p>This constant is documented in the Linux documentation.</p>

  748. <div class="availability docutils container">

  749. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 4.1.</p>

  750. </div>

  751. <div class="versionadded">

  752. <p><span class="versionmodified added">New in version 3.9.</span></p>

  753. </div>

  754. </dd></dl>

  755. 

  756. <dl class="py data">

  757. <dt class="sig sig-object py" id="socket.CAN_ISOTP">

  758. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CAN_ISOTP</span></span><a class="headerlink" href="#socket.CAN_ISOTP" title="Link to this definition">¶</a></dt>

  759. <dd><p>CAN_ISOTP, in the CAN protocol family, is the ISO-TP (ISO 15765-2) protocol.

  760. ISO-TP constants, documented in the Linux documentation.</p>

  761. <div class="availability docutils container">

  762. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.25.</p>

  763. </div>

  764. <div class="versionadded">

  765. <p><span class="versionmodified added">New in version 3.7.</span></p>

  766. </div>

  767. </dd></dl>

  768. 

  769. <dl class="py data">

  770. <dt class="sig sig-object py" id="socket.CAN_J1939">

  771. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CAN_J1939</span></span><a class="headerlink" href="#socket.CAN_J1939" title="Link to this definition">¶</a></dt>

  772. <dd><p>CAN_J1939, in the CAN protocol family, is the SAE J1939 protocol.

  773. J1939 constants, documented in the Linux documentation.</p>

  774. <div class="availability docutils container">

  775. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 5.4.</p>

  776. </div>

  777. <div class="versionadded">

  778. <p><span class="versionmodified added">New in version 3.9.</span></p>

  779. </div>

  780. </dd></dl>

  781. 

  782. <dl class="py data">

  783. <dt class="sig sig-object py" id="socket.AF_DIVERT">

  784. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_DIVERT</span></span><a class="headerlink" href="#socket.AF_DIVERT" title="Link to this definition">¶</a></dt>

  785. <dt class="sig sig-object py" id="socket.PF_DIVERT">

  786. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">PF_DIVERT</span></span><a class="headerlink" href="#socket.PF_DIVERT" title="Link to this definition">¶</a></dt>

  787. <dd><p>These two constants, documented in the FreeBSD divert(4) manual page, are

  788. also defined in the socket module.</p>

  789. <div class="availability docutils container">

  790. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: FreeBSD &gt;= 14.0.</p>

  791. </div>

  792. <div class="versionadded">

  793. <p><span class="versionmodified added">New in version 3.12.</span></p>

  794. </div>

  795. </dd></dl>

  796. 

  797. <dl class="py data">

  798. <dt class="sig sig-object py" id="socket.AF_PACKET">

  799. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_PACKET</span></span><a class="headerlink" href="#socket.AF_PACKET" title="Link to this definition">¶</a></dt>

  800. <dt class="sig sig-object py" id="socket.PF_PACKET">

  801. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">PF_PACKET</span></span><a class="headerlink" href="#socket.PF_PACKET" title="Link to this definition">¶</a></dt>

  802. <dt class="sig sig-object py">

  803. <span class="sig-name descname"><span class="pre">PACKET_*</span></span></dt>

  804. <dd><p>Many constants of these forms, documented in the Linux documentation, are

  805. also defined in the socket module.</p>

  806. <div class="availability docutils container">

  807. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.2.</p>

  808. </div>

  809. </dd></dl>

  810. 

  811. <dl class="py data">

  812. <dt class="sig sig-object py" id="socket.ETH_P_ALL">

  813. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ETH_P_ALL</span></span><a class="headerlink" href="#socket.ETH_P_ALL" title="Link to this definition">¶</a></dt>

  814. <dd><p><code class="xref py py-data docutils literal notranslate"><span class="pre">ETH_P_ALL</span></code> can be used in the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-class docutils literal notranslate"><span class="pre">socket</span></code></a>

  815. constructor as <em>proto</em> for the <a class="reference internal" href="#socket.AF_PACKET" title="socket.AF_PACKET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_PACKET</span></code></a> family in order to

  816. capture every packet, regardless of protocol.</p>

  817. <p>For more information, see the <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/packet(7)">packet(7)</a></em> manpage.</p>

  818. <div class="availability docutils container">

  819. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux.</p>

  820. </div>

  821. <div class="versionadded">

  822. <p><span class="versionmodified added">New in version 3.12.</span></p>

  823. </div>

  824. </dd></dl>

  825. 

  826. <dl class="py data">

  827. <dt class="sig sig-object py" id="socket.AF_RDS">

  828. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_RDS</span></span><a class="headerlink" href="#socket.AF_RDS" title="Link to this definition">¶</a></dt>

  829. <dt class="sig sig-object py" id="socket.PF_RDS">

  830. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">PF_RDS</span></span><a class="headerlink" href="#socket.PF_RDS" title="Link to this definition">¶</a></dt>

  831. <dt class="sig sig-object py" id="socket.SOL_RDS">

  832. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOL_RDS</span></span><a class="headerlink" href="#socket.SOL_RDS" title="Link to this definition">¶</a></dt>

  833. <dt class="sig sig-object py">

  834. <span class="sig-name descname"><span class="pre">RDS_*</span></span></dt>

  835. <dd><p>Many constants of these forms, documented in the Linux documentation, are

  836. also defined in the socket module.</p>

  837. <div class="availability docutils container">

  838. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.30.</p>

  839. </div>

  840. <div class="versionadded">

  841. <p><span class="versionmodified added">New in version 3.3.</span></p>

  842. </div>

  843. </dd></dl>

  844. 

  845. <dl class="py data">

  846. <dt class="sig sig-object py" id="socket.SIO_RCVALL">

  847. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SIO_RCVALL</span></span><a class="headerlink" href="#socket.SIO_RCVALL" title="Link to this definition">¶</a></dt>

  848. <dt class="sig sig-object py" id="socket.SIO_KEEPALIVE_VALS">

  849. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SIO_KEEPALIVE_VALS</span></span><a class="headerlink" href="#socket.SIO_KEEPALIVE_VALS" title="Link to this definition">¶</a></dt>

  850. <dt class="sig sig-object py" id="socket.SIO_LOOPBACK_FAST_PATH">

  851. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SIO_LOOPBACK_FAST_PATH</span></span><a class="headerlink" href="#socket.SIO_LOOPBACK_FAST_PATH" title="Link to this definition">¶</a></dt>

  852. <dt class="sig sig-object py">

  853. <span class="sig-name descname"><span class="pre">RCVALL_*</span></span></dt>

  854. <dd><p>Constants for Windows’ WSAIoctl(). The constants are used as arguments to the

  855. <a class="reference internal" href="#socket.socket.ioctl" title="socket.socket.ioctl"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ioctl()</span></code></a> method of socket objects.</p>

  856. <div class="versionchanged">

  857. <p><span class="versionmodified changed">Changed in version 3.6: </span><code class="docutils literal notranslate"><span class="pre">SIO_LOOPBACK_FAST_PATH</span></code> was added.</p>

  858. </div>

  859. </dd></dl>

  860. 

  861. <dl class="py data">

  862. <dt class="sig sig-object py">

  863. <span class="sig-name descname"><span class="pre">TIPC_*</span></span></dt>

  864. <dd><p>TIPC related constants, matching the ones exported by the C socket API. See

  865. the TIPC documentation for more information.</p>

  866. </dd></dl>

  867. 

  868. <dl class="py data">

  869. <dt class="sig sig-object py" id="socket.AF_ALG">

  870. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_ALG</span></span><a class="headerlink" href="#socket.AF_ALG" title="Link to this definition">¶</a></dt>

  871. <dt class="sig sig-object py" id="socket.SOL_ALG">

  872. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SOL_ALG</span></span><a class="headerlink" href="#socket.SOL_ALG" title="Link to this definition">¶</a></dt>

  873. <dt class="sig sig-object py">

  874. <span class="sig-name descname"><span class="pre">ALG_*</span></span></dt>

  875. <dd><p>Constants for Linux Kernel cryptography.</p>

  876. <div class="availability docutils container">

  877. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.38.</p>

  878. </div>

  879. <div class="versionadded">

  880. <p><span class="versionmodified added">New in version 3.6.</span></p>

  881. </div>

  882. </dd></dl>

  883. 

  884. <dl class="py data">

  885. <dt class="sig sig-object py" id="socket.AF_VSOCK">

  886. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_VSOCK</span></span><a class="headerlink" href="#socket.AF_VSOCK" title="Link to this definition">¶</a></dt>

  887. <dt class="sig sig-object py" id="socket.IOCTL_VM_SOCKETS_GET_LOCAL_CID">

  888. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">IOCTL_VM_SOCKETS_GET_LOCAL_CID</span></span><a class="headerlink" href="#socket.IOCTL_VM_SOCKETS_GET_LOCAL_CID" title="Link to this definition">¶</a></dt>

  889. <dt class="sig sig-object py">

  890. <span class="sig-name descname"><span class="pre">VMADDR*</span></span></dt>

  891. <dt class="sig sig-object py">

  892. <span class="sig-name descname"><span class="pre">SO_VM*</span></span></dt>

  893. <dd><p>Constants for Linux host/guest communication.</p>

  894. <div class="availability docutils container">

  895. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 4.8.</p>

  896. </div>

  897. <div class="versionadded">

  898. <p><span class="versionmodified added">New in version 3.7.</span></p>

  899. </div>

  900. </dd></dl>

  901. 

  902. <dl class="py data">

  903. <dt class="sig sig-object py" id="socket.AF_LINK">

  904. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_LINK</span></span><a class="headerlink" href="#socket.AF_LINK" title="Link to this definition">¶</a></dt>

  905. <dd><div class="availability docutils container">

  906. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: BSD, macOS.</p>

  907. </div>

  908. <div class="versionadded">

  909. <p><span class="versionmodified added">New in version 3.4.</span></p>

  910. </div>

  911. </dd></dl>

  912. 

  913. <dl class="py data">

  914. <dt class="sig sig-object py" id="socket.has_ipv6">

  915. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">has_ipv6</span></span><a class="headerlink" href="#socket.has_ipv6" title="Link to this definition">¶</a></dt>

  916. <dd><p>This constant contains a boolean value which indicates if IPv6 is supported on

  917. this platform.</p>

  918. </dd></dl>

  919. 

  920. <dl class="py data">

  921. <dt class="sig sig-object py" id="socket.BDADDR_ANY">

  922. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">BDADDR_ANY</span></span><a class="headerlink" href="#socket.BDADDR_ANY" title="Link to this definition">¶</a></dt>

  923. <dt class="sig sig-object py" id="socket.BDADDR_LOCAL">

  924. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">BDADDR_LOCAL</span></span><a class="headerlink" href="#socket.BDADDR_LOCAL" title="Link to this definition">¶</a></dt>

  925. <dd><p>These are string constants containing Bluetooth addresses with special

  926. meanings. For example, <a class="reference internal" href="#socket.BDADDR_ANY" title="socket.BDADDR_ANY"><code class="xref py py-const docutils literal notranslate"><span class="pre">BDADDR_ANY</span></code></a> can be used to indicate

  927. any address when specifying the binding socket with

  928. <code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_RFCOMM</span></code>.</p>

  929. </dd></dl>

  930. 

  931. <dl class="py data">

  932. <dt class="sig sig-object py" id="socket.HCI_FILTER">

  933. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HCI_FILTER</span></span><a class="headerlink" href="#socket.HCI_FILTER" title="Link to this definition">¶</a></dt>

  934. <dt class="sig sig-object py" id="socket.HCI_TIME_STAMP">

  935. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HCI_TIME_STAMP</span></span><a class="headerlink" href="#socket.HCI_TIME_STAMP" title="Link to this definition">¶</a></dt>

  936. <dt class="sig sig-object py" id="socket.HCI_DATA_DIR">

  937. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HCI_DATA_DIR</span></span><a class="headerlink" href="#socket.HCI_DATA_DIR" title="Link to this definition">¶</a></dt>

  938. <dd><p>For use with <code class="xref py py-const docutils literal notranslate"><span class="pre">BTPROTO_HCI</span></code>. <a class="reference internal" href="#socket.HCI_FILTER" title="socket.HCI_FILTER"><code class="xref py py-const docutils literal notranslate"><span class="pre">HCI_FILTER</span></code></a> is not

  939. available for NetBSD or DragonFlyBSD. <a class="reference internal" href="#socket.HCI_TIME_STAMP" title="socket.HCI_TIME_STAMP"><code class="xref py py-const docutils literal notranslate"><span class="pre">HCI_TIME_STAMP</span></code></a> and

  940. <a class="reference internal" href="#socket.HCI_DATA_DIR" title="socket.HCI_DATA_DIR"><code class="xref py py-const docutils literal notranslate"><span class="pre">HCI_DATA_DIR</span></code></a> are not available for FreeBSD, NetBSD, or

  941. DragonFlyBSD.</p>

  942. </dd></dl>

  943. 

  944. <dl class="py data">

  945. <dt class="sig sig-object py" id="socket.AF_QIPCRTR">

  946. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_QIPCRTR</span></span><a class="headerlink" href="#socket.AF_QIPCRTR" title="Link to this definition">¶</a></dt>

  947. <dd><p>Constant for Qualcomm’s IPC router protocol, used to communicate with

  948. service providing remote processors.</p>

  949. <div class="availability docutils container">

  950. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 4.7.</p>

  951. </div>

  952. </dd></dl>

  953. 

  954. <dl class="py data">

  955. <dt class="sig sig-object py" id="socket.SCM_CREDS2">

  956. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SCM_CREDS2</span></span><a class="headerlink" href="#socket.SCM_CREDS2" title="Link to this definition">¶</a></dt>

  957. <dt class="sig sig-object py" id="socket.LOCAL_CREDS">

  958. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">LOCAL_CREDS</span></span><a class="headerlink" href="#socket.LOCAL_CREDS" title="Link to this definition">¶</a></dt>

  959. <dt class="sig sig-object py" id="socket.LOCAL_CREDS_PERSISTENT">

  960. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">LOCAL_CREDS_PERSISTENT</span></span><a class="headerlink" href="#socket.LOCAL_CREDS_PERSISTENT" title="Link to this definition">¶</a></dt>

  961. <dd><p>LOCAL_CREDS and LOCAL_CREDS_PERSISTENT can be used

  962. with SOCK_DGRAM, SOCK_STREAM sockets, equivalent to

  963. Linux/DragonFlyBSD SO_PASSCRED, while LOCAL_CREDS

  964. sends the credentials at first read, LOCAL_CREDS_PERSISTENT

  965. sends for each read, SCM_CREDS2 must be then used for

  966. the latter for the message type.</p>

  967. <div class="versionadded">

  968. <p><span class="versionmodified added">New in version 3.11.</span></p>

  969. </div>

  970. <div class="availability docutils container">

  971. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: FreeBSD.</p>

  972. </div>

  973. </dd></dl>

  974. 

  975. <dl class="py data">

  976. <dt class="sig sig-object py" id="socket.SO_INCOMING_CPU">

  977. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SO_INCOMING_CPU</span></span><a class="headerlink" href="#socket.SO_INCOMING_CPU" title="Link to this definition">¶</a></dt>

  978. <dd><blockquote>

  979. <div><p>Constant to optimize CPU locality, to be used in conjunction with

  980. <code class="xref py py-data docutils literal notranslate"><span class="pre">SO_REUSEPORT</span></code>.</p>

  981. </div></blockquote>

  982. <div class="versionadded">

  983. <p><span class="versionmodified added">New in version 3.11.</span></p>

  984. </div>

  985. <div class="availability docutils container">

  986. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 3.9</p>

  987. </div>

  988. </dd></dl>

  989. 

  990. <dl class="py data">

  991. <dt class="sig sig-object py" id="socket.AF_HYPERV">

  992. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">AF_HYPERV</span></span><a class="headerlink" href="#socket.AF_HYPERV" title="Link to this definition">¶</a></dt>

  993. <dt class="sig sig-object py" id="socket.HV_PROTOCOL_RAW">

  994. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_PROTOCOL_RAW</span></span><a class="headerlink" href="#socket.HV_PROTOCOL_RAW" title="Link to this definition">¶</a></dt>

  995. <dt class="sig sig-object py" id="socket.HVSOCKET_CONNECT_TIMEOUT">

  996. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HVSOCKET_CONNECT_TIMEOUT</span></span><a class="headerlink" href="#socket.HVSOCKET_CONNECT_TIMEOUT" title="Link to this definition">¶</a></dt>

  997. <dt class="sig sig-object py" id="socket.HVSOCKET_CONNECT_TIMEOUT_MAX">

  998. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HVSOCKET_CONNECT_TIMEOUT_MAX</span></span><a class="headerlink" href="#socket.HVSOCKET_CONNECT_TIMEOUT_MAX" title="Link to this definition">¶</a></dt>

  999. <dt class="sig sig-object py" id="socket.HVSOCKET_CONNECTED_SUSPEND">

  1000. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HVSOCKET_CONNECTED_SUSPEND</span></span><a class="headerlink" href="#socket.HVSOCKET_CONNECTED_SUSPEND" title="Link to this definition">¶</a></dt>

  1001. <dt class="sig sig-object py" id="socket.HVSOCKET_ADDRESS_FLAG_PASSTHRU">

  1002. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HVSOCKET_ADDRESS_FLAG_PASSTHRU</span></span><a class="headerlink" href="#socket.HVSOCKET_ADDRESS_FLAG_PASSTHRU" title="Link to this definition">¶</a></dt>

  1003. <dt class="sig sig-object py" id="socket.HV_GUID_ZERO">

  1004. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_ZERO</span></span><a class="headerlink" href="#socket.HV_GUID_ZERO" title="Link to this definition">¶</a></dt>

  1005. <dt class="sig sig-object py" id="socket.HV_GUID_WILDCARD">

  1006. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_WILDCARD</span></span><a class="headerlink" href="#socket.HV_GUID_WILDCARD" title="Link to this definition">¶</a></dt>

  1007. <dt class="sig sig-object py" id="socket.HV_GUID_BROADCAST">

  1008. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_BROADCAST</span></span><a class="headerlink" href="#socket.HV_GUID_BROADCAST" title="Link to this definition">¶</a></dt>

  1009. <dt class="sig sig-object py" id="socket.HV_GUID_CHILDREN">

  1010. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_CHILDREN</span></span><a class="headerlink" href="#socket.HV_GUID_CHILDREN" title="Link to this definition">¶</a></dt>

  1011. <dt class="sig sig-object py" id="socket.HV_GUID_LOOPBACK">

  1012. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_LOOPBACK</span></span><a class="headerlink" href="#socket.HV_GUID_LOOPBACK" title="Link to this definition">¶</a></dt>

  1013. <dt class="sig sig-object py" id="socket.HV_GUID_PARENT">

  1014. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">HV_GUID_PARENT</span></span><a class="headerlink" href="#socket.HV_GUID_PARENT" title="Link to this definition">¶</a></dt>

  1015. <dd><p>Constants for Windows Hyper-V sockets for host/guest communications.</p>

  1016. <div class="availability docutils container">

  1017. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Windows.</p>

  1018. </div>

  1019. <div class="versionadded">

  1020. <p><span class="versionmodified added">New in version 3.12.</span></p>

  1021. </div>

  1022. </dd></dl>

  1023. 

  1024. <dl class="py data" id="socket-ethernet-types">

  1025. <dt class="sig sig-object py" id="socket.ETHERTYPE_ARP">

  1026. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ETHERTYPE_ARP</span></span><a class="headerlink" href="#socket.ETHERTYPE_ARP" title="Link to this definition">¶</a></dt>

  1027. <dt class="sig sig-object py" id="socket.ETHERTYPE_IP">

  1028. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ETHERTYPE_IP</span></span><a class="headerlink" href="#socket.ETHERTYPE_IP" title="Link to this definition">¶</a></dt>

  1029. <dt class="sig sig-object py" id="socket.ETHERTYPE_IPV6">

  1030. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ETHERTYPE_IPV6</span></span><a class="headerlink" href="#socket.ETHERTYPE_IPV6" title="Link to this definition">¶</a></dt>

  1031. <dt class="sig sig-object py" id="socket.ETHERTYPE_VLAN">

  1032. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ETHERTYPE_VLAN</span></span><a class="headerlink" href="#socket.ETHERTYPE_VLAN" title="Link to this definition">¶</a></dt>

  1033. <dd><p><a class="reference external" href="https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.txt">IEEE 802.3 protocol number</a>.

  1034. constants.</p>

  1035. <div class="availability docutils container">

  1036. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux, FreeBSD, macOS.</p>

  1037. </div>

  1038. <div class="versionadded">

  1039. <p><span class="versionmodified added">New in version 3.12.</span></p>

  1040. </div>

  1041. </dd></dl>

  1042. 

  1043. </section>

  1044. <section id="functions">

  1045. <h3>Functions<a class="headerlink" href="#functions" title="Link to this heading">¶</a></h3>

  1046. <section id="creating-sockets">

  1047. <h4>Creating sockets<a class="headerlink" href="#creating-sockets" title="Link to this heading">¶</a></h4>

  1048. <p>The following functions all create <a class="reference internal" href="#socket-objects"><span class="std std-ref">socket objects</span></a>.</p>

  1049. <dl class="py class">

  1050. <dt class="sig sig-object py" id="socket.socket">

  1051. <em class="property"><span class="pre">class</span><span class="w"> </span></em><span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">socket</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">family</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">AF_INET</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">type</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">SOCK_STREAM</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">proto</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">fileno</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket" title="Link to this definition">¶</a></dt>

  1052. <dd><p>Create a new socket using the given address family, socket type and protocol

  1053. number.  The address family should be <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a> (the default),

  1054. <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>, <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a>, <a class="reference internal" href="#socket.AF_CAN" title="socket.AF_CAN"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_CAN</span></code></a>, <a class="reference internal" href="#socket.AF_PACKET" title="socket.AF_PACKET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_PACKET</span></code></a>,

  1055. or <a class="reference internal" href="#socket.AF_RDS" title="socket.AF_RDS"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_RDS</span></code></a>. The socket type should be <a class="reference internal" href="#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code></a> (the

  1056. default), <a class="reference internal" href="#socket.SOCK_DGRAM" title="socket.SOCK_DGRAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_DGRAM</span></code></a>, <a class="reference internal" href="#socket.SOCK_RAW" title="socket.SOCK_RAW"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_RAW</span></code></a> or perhaps one of the other

  1057. <code class="docutils literal notranslate"><span class="pre">SOCK_</span></code> constants. The protocol number is usually zero and may be omitted

  1058. or in the case where the address family is <a class="reference internal" href="#socket.AF_CAN" title="socket.AF_CAN"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_CAN</span></code></a> the protocol

  1059. should be one of <code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_RAW</span></code>, <a class="reference internal" href="#socket.CAN_BCM" title="socket.CAN_BCM"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_BCM</span></code></a>, <a class="reference internal" href="#socket.CAN_ISOTP" title="socket.CAN_ISOTP"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_ISOTP</span></code></a> or

  1060. <a class="reference internal" href="#socket.CAN_J1939" title="socket.CAN_J1939"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_J1939</span></code></a>.</p>

  1061. <p>If <em>fileno</em> is specified, the values for <em>family</em>, <em>type</em>, and <em>proto</em> are

  1062. auto-detected from the specified file descriptor.  Auto-detection can be

  1063. overruled by calling the function with explicit <em>family</em>, <em>type</em>, or <em>proto</em>

  1064. arguments.  This only affects how Python represents e.g. the return value

  1065. of <a class="reference internal" href="#socket.socket.getpeername" title="socket.socket.getpeername"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.getpeername()</span></code></a> but not the actual OS resource.  Unlike

  1066. <a class="reference internal" href="#socket.fromfd" title="socket.fromfd"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket.fromfd()</span></code></a>, <em>fileno</em> will return the same socket and not a

  1067. duplicate. This may help close a detached socket using

  1068. <a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.close()</span></code></a>.</p>

  1069. <p>The newly created socket is <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">non-inheritable</span></a>.</p>

  1070. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.__new__</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">family</span></code>, <code class="docutils literal notranslate"><span class="pre">type</span></code>, <code class="docutils literal notranslate"><span class="pre">protocol</span></code>.</p>

  1071. <div class="versionchanged">

  1072. <p><span class="versionmodified changed">Changed in version 3.3: </span>The AF_CAN family was added.

  1073. The AF_RDS family was added.</p>

  1074. </div>

  1075. <div class="versionchanged">

  1076. <p><span class="versionmodified changed">Changed in version 3.4: </span>The CAN_BCM protocol was added.</p>

  1077. </div>

  1078. <div class="versionchanged">

  1079. <p><span class="versionmodified changed">Changed in version 3.4: </span>The returned socket is now non-inheritable.</p>

  1080. </div>

  1081. <div class="versionchanged">

  1082. <p><span class="versionmodified changed">Changed in version 3.7: </span>The CAN_ISOTP protocol was added.</p>

  1083. </div>

  1084. <div class="versionchanged">

  1085. <p><span class="versionmodified changed">Changed in version 3.7: </span>When <a class="reference internal" href="#socket.SOCK_NONBLOCK" title="socket.SOCK_NONBLOCK"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_NONBLOCK</span></code></a> or <a class="reference internal" href="#socket.SOCK_CLOEXEC" title="socket.SOCK_CLOEXEC"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_CLOEXEC</span></code></a>

  1086. bit flags are applied to <em>type</em> they are cleared, and

  1087. <a class="reference internal" href="#socket.socket.type" title="socket.socket.type"><code class="xref py py-attr docutils literal notranslate"><span class="pre">socket.type</span></code></a> will not reflect them.  They are still passed

  1088. to the underlying system <code class="docutils literal notranslate"><span class="pre">socket()</span></code> call.  Therefore,</p>

  1089. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">sock</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span>

  1090.     <span class="n">socket</span><span class="o">.</span><span class="n">AF_INET</span><span class="p">,</span>

  1091.     <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span> <span class="o">|</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_NONBLOCK</span><span class="p">)</span>

  1092. </pre></div>

  1093. </div>

  1094. <p>will still create a non-blocking socket on OSes that support

  1095. <code class="docutils literal notranslate"><span class="pre">SOCK_NONBLOCK</span></code>, but <code class="docutils literal notranslate"><span class="pre">sock.type</span></code> will be set to

  1096. <code class="docutils literal notranslate"><span class="pre">socket.SOCK_STREAM</span></code>.</p>

  1097. </div>

  1098. <div class="versionchanged">

  1099. <p><span class="versionmodified changed">Changed in version 3.9: </span>The CAN_J1939 protocol was added.</p>

  1100. </div>

  1101. <div class="versionchanged">

  1102. <p><span class="versionmodified changed">Changed in version 3.10: </span>The IPPROTO_MPTCP protocol was added.</p>

  1103. </div>

  1104. </dd></dl>

  1105. 

  1106. <dl class="py function">

  1107. <dt class="sig sig-object py" id="socket.socketpair">

  1108. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">socketpair</span></span><span class="sig-paren">(</span><span class="optional">[</span><em class="sig-param"><span class="n"><span class="pre">family</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">type</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">proto</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socketpair" title="Link to this definition">¶</a></dt>

  1109. <dd><p>Build a pair of connected socket objects using the given address family, socket

  1110. type, and protocol number.  Address family, socket type, and protocol number are

  1111. as for the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a> function above. The default family is <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a>

  1112. if defined on the platform; otherwise, the default is <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a>.</p>

  1113. <p>The newly created sockets are <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">non-inheritable</span></a>.</p>

  1114. <div class="versionchanged">

  1115. <p><span class="versionmodified changed">Changed in version 3.2: </span>The returned socket objects now support the whole socket API, rather

  1116. than a subset.</p>

  1117. </div>

  1118. <div class="versionchanged">

  1119. <p><span class="versionmodified changed">Changed in version 3.4: </span>The returned sockets are now non-inheritable.</p>

  1120. </div>

  1121. <div class="versionchanged">

  1122. <p><span class="versionmodified changed">Changed in version 3.5: </span>Windows support added.</p>

  1123. </div>

  1124. </dd></dl>

  1125. 

  1126. <dl class="py function">

  1127. <dt class="sig sig-object py" id="socket.create_connection">

  1128. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">create_connection</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">timeout</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">GLOBAL_DEFAULT</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">source_address</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">all_errors</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.create_connection" title="Link to this definition">¶</a></dt>

  1129. <dd><p>Connect to a TCP service listening on the internet <em>address</em> (a 2-tuple

  1130. <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code>), and return the socket object.  This is a higher-level

  1131. function than <a class="reference internal" href="#socket.socket.connect" title="socket.socket.connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.connect()</span></code></a>: if <em>host</em> is a non-numeric hostname,

  1132. it will try to resolve it for both <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-data docutils literal notranslate"><span class="pre">AF_INET</span></code></a> and <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-data docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>,

  1133. and then try to connect to all possible addresses in turn until a

  1134. connection succeeds.  This makes it easy to write clients that are

  1135. compatible to both IPv4 and IPv6.</p>

  1136. <p>Passing the optional <em>timeout</em> parameter will set the timeout on the

  1137. socket instance before attempting to connect.  If no <em>timeout</em> is

  1138. supplied, the global default timeout setting returned by

  1139. <a class="reference internal" href="#socket.getdefaulttimeout" title="socket.getdefaulttimeout"><code class="xref py py-func docutils literal notranslate"><span class="pre">getdefaulttimeout()</span></code></a> is used.</p>

  1140. <p>If supplied, <em>source_address</em> must be a 2-tuple <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code> for the

  1141. socket to bind to as its source address before connecting.  If host or port

  1142. are ‘’ or 0 respectively the OS default behavior will be used.</p>

  1143. <p>When a connection cannot be created, an exception is raised. By default,

  1144. it is the exception from the last address in the list. If <em>all_errors</em>

  1145. is <code class="docutils literal notranslate"><span class="pre">True</span></code>, it is an <a class="reference internal" href="exceptions.html#ExceptionGroup" title="ExceptionGroup"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ExceptionGroup</span></code></a> containing the errors of all

  1146. attempts.</p>

  1147. <div class="versionchanged">

  1148. <p><span class="versionmodified changed">Changed in version 3.2: </span><em>source_address</em> was added.</p>

  1149. </div>

  1150. <div class="versionchanged">

  1151. <p><span class="versionmodified changed">Changed in version 3.11: </span><em>all_errors</em> was added.</p>

  1152. </div>

  1153. </dd></dl>

  1154. 

  1155. <dl class="py function">

  1156. <dt class="sig sig-object py" id="socket.create_server">

  1157. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">create_server</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">family</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">AF_INET</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">backlog</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">reuse_port</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">dualstack_ipv6</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">False</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.create_server" title="Link to this definition">¶</a></dt>

  1158. <dd><p>Convenience function which creates a TCP socket bound to <em>address</em> (a 2-tuple

  1159. <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code>) and returns the socket object.</p>

  1160. <p><em>family</em> should be either <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-data docutils literal notranslate"><span class="pre">AF_INET</span></code></a> or <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-data docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>.

  1161. <em>backlog</em> is the queue size passed to <a class="reference internal" href="#socket.socket.listen" title="socket.socket.listen"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.listen()</span></code></a>; if not specified

  1162. , a default reasonable value is chosen.

  1163. <em>reuse_port</em> dictates whether to set the <code class="xref py py-data docutils literal notranslate"><span class="pre">SO_REUSEPORT</span></code> socket option.</p>

  1164. <p>If <em>dualstack_ipv6</em> is true and the platform supports it the socket will

  1165. be able to accept both IPv4 and IPv6 connections, else it will raise

  1166. <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a>. Most POSIX platforms and Windows are supposed to support

  1167. this functionality.

  1168. When this functionality is enabled the address returned by

  1169. <a class="reference internal" href="#socket.socket.getpeername" title="socket.socket.getpeername"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.getpeername()</span></code></a> when an IPv4 connection occurs will be an IPv6

  1170. address represented as an IPv4-mapped IPv6 address.

  1171. If <em>dualstack_ipv6</em> is false it will explicitly disable this functionality

  1172. on platforms that enable it by default (e.g. Linux).

  1173. This parameter can be used in conjunction with <a class="reference internal" href="#socket.has_dualstack_ipv6" title="socket.has_dualstack_ipv6"><code class="xref py py-func docutils literal notranslate"><span class="pre">has_dualstack_ipv6()</span></code></a>:</p>

  1174. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">socket</span>

  1175. 

  1176. <span class="n">addr</span> <span class="o">=</span> <span class="p">(</span><span class="s2">&quot;&quot;</span><span class="p">,</span> <span class="mi">8080</span><span class="p">)</span>  <span class="c1"># all interfaces, port 8080</span>

  1177. <span class="k">if</span> <span class="n">socket</span><span class="o">.</span><span class="n">has_dualstack_ipv6</span><span class="p">():</span>

  1178.     <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">create_server</span><span class="p">(</span><span class="n">addr</span><span class="p">,</span> <span class="n">family</span><span class="o">=</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_INET6</span><span class="p">,</span> <span class="n">dualstack_ipv6</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>

  1179. <span class="k">else</span><span class="p">:</span>

  1180.     <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">create_server</span><span class="p">(</span><span class="n">addr</span><span class="p">)</span>

  1181. </pre></div>

  1182. </div>

  1183. <div class="admonition note">

  1184. <p class="admonition-title">Note</p>

  1185. <p>On POSIX platforms the <code class="xref py py-data docutils literal notranslate"><span class="pre">SO_REUSEADDR</span></code> socket option is set in order to

  1186. immediately reuse previous sockets which were bound on the same <em>address</em>

  1187. and remained in TIME_WAIT state.</p>

  1188. </div>

  1189. <div class="versionadded">

  1190. <p><span class="versionmodified added">New in version 3.8.</span></p>

  1191. </div>

  1192. </dd></dl>

  1193. 

  1194. <dl class="py function">

  1195. <dt class="sig sig-object py" id="socket.has_dualstack_ipv6">

  1196. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">has_dualstack_ipv6</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.has_dualstack_ipv6" title="Link to this definition">¶</a></dt>

  1197. <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if the platform supports creating a TCP socket which can

  1198. handle both IPv4 and IPv6 connections.</p>

  1199. <div class="versionadded">

  1200. <p><span class="versionmodified added">New in version 3.8.</span></p>

  1201. </div>

  1202. </dd></dl>

  1203. 

  1204. <dl class="py function">

  1205. <dt class="sig sig-object py" id="socket.fromfd">

  1206. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">fromfd</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">fd</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">family</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">type</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">proto</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.fromfd" title="Link to this definition">¶</a></dt>

  1207. <dd><p>Duplicate the file descriptor <em>fd</em> (an integer as returned by a file object’s

  1208. <a class="reference internal" href="io.html#io.IOBase.fileno" title="io.IOBase.fileno"><code class="xref py py-meth docutils literal notranslate"><span class="pre">fileno()</span></code></a> method) and build a socket object from the result.  Address

  1209. family, socket type and protocol number are as for the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a> function

  1210. above. The file descriptor should refer to a socket, but this is not checked —

  1211. subsequent operations on the object may fail if the file descriptor is invalid.

  1212. This function is rarely needed, but can be used to get or set socket options on

  1213. a socket passed to a program as standard input or output (such as a server

  1214. started by the Unix inet daemon).  The socket is assumed to be in blocking mode.</p>

  1215. <p>The newly created socket is <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">non-inheritable</span></a>.</p>

  1216. <div class="versionchanged">

  1217. <p><span class="versionmodified changed">Changed in version 3.4: </span>The returned socket is now non-inheritable.</p>

  1218. </div>

  1219. </dd></dl>

  1220. 

  1221. <dl class="py function">

  1222. <dt class="sig sig-object py" id="socket.fromshare">

  1223. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">fromshare</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">data</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.fromshare" title="Link to this definition">¶</a></dt>

  1224. <dd><p>Instantiate a socket from data obtained from the <a class="reference internal" href="#socket.socket.share" title="socket.socket.share"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.share()</span></code></a>

  1225. method.  The socket is assumed to be in blocking mode.</p>

  1226. <div class="availability docutils container">

  1227. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Windows.</p>

  1228. </div>

  1229. <div class="versionadded">

  1230. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1231. </div>

  1232. </dd></dl>

  1233. 

  1234. <dl class="py data">

  1235. <dt class="sig sig-object py" id="socket.SocketType">

  1236. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">SocketType</span></span><a class="headerlink" href="#socket.SocketType" title="Link to this definition">¶</a></dt>

  1237. <dd><p>This is a Python type object that represents the socket object type. It is the

  1238. same as <code class="docutils literal notranslate"><span class="pre">type(socket(...))</span></code>.</p>

  1239. </dd></dl>

  1240. 

  1241. </section>

  1242. <section id="other-functions">

  1243. <h4>Other functions<a class="headerlink" href="#other-functions" title="Link to this heading">¶</a></h4>

  1244. <p>The <a class="reference internal" href="#module-socket" title="socket: Low-level networking interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code></a> module also offers various network-related services:</p>

  1245. <dl class="py function">

  1246. <dt class="sig sig-object py" id="socket.close">

  1247. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">fd</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.close" title="Link to this definition">¶</a></dt>

  1248. <dd><p>Close a socket file descriptor. This is like <a class="reference internal" href="os.html#os.close" title="os.close"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.close()</span></code></a>, but for

  1249. sockets. On some platforms (most noticeable Windows) <a class="reference internal" href="os.html#os.close" title="os.close"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.close()</span></code></a>

  1250. does not work for socket file descriptors.</p>

  1251. <div class="versionadded">

  1252. <p><span class="versionmodified added">New in version 3.7.</span></p>

  1253. </div>

  1254. </dd></dl>

  1255. 

  1256. <dl class="py function">

  1257. <dt class="sig sig-object py" id="socket.getaddrinfo">

  1258. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getaddrinfo</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">host</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">port</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">family</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">type</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">proto</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.getaddrinfo" title="Link to this definition">¶</a></dt>

  1259. <dd><p>Translate the <em>host</em>/<em>port</em> argument into a sequence of 5-tuples that contain

  1260. all the necessary arguments for creating a socket connected to that service.

  1261. <em>host</em> is a domain name, a string representation of an IPv4/v6 address

  1262. or <code class="docutils literal notranslate"><span class="pre">None</span></code>. <em>port</em> is a string service name such as <code class="docutils literal notranslate"><span class="pre">'http'</span></code>, a numeric

  1263. port number or <code class="docutils literal notranslate"><span class="pre">None</span></code>.  By passing <code class="docutils literal notranslate"><span class="pre">None</span></code> as the value of <em>host</em>

  1264. and <em>port</em>, you can pass <code class="docutils literal notranslate"><span class="pre">NULL</span></code> to the underlying C API.</p>

  1265. <p>The <em>family</em>, <em>type</em> and <em>proto</em> arguments can be optionally specified

  1266. in order to narrow the list of addresses returned.  Passing zero as a

  1267. value for each of these arguments selects the full range of results.

  1268. The <em>flags</em> argument can be one or several of the <code class="docutils literal notranslate"><span class="pre">AI_*</span></code> constants,

  1269. and will influence how results are computed and returned.

  1270. For example, <code class="xref py py-const docutils literal notranslate"><span class="pre">AI_NUMERICHOST</span></code> will disable domain name resolution

  1271. and will raise an error if <em>host</em> is a domain name.</p>

  1272. <p>The function returns a list of 5-tuples with the following structure:</p>

  1273. <p><code class="docutils literal notranslate"><span class="pre">(family,</span> <span class="pre">type,</span> <span class="pre">proto,</span> <span class="pre">canonname,</span> <span class="pre">sockaddr)</span></code></p>

  1274. <p>In these tuples, <em>family</em>, <em>type</em>, <em>proto</em> are all integers and are

  1275. meant to be passed to the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a> function.  <em>canonname</em> will be

  1276. a string representing the canonical name of the <em>host</em> if

  1277. <code class="xref py py-const docutils literal notranslate"><span class="pre">AI_CANONNAME</span></code> is part of the <em>flags</em> argument; else <em>canonname</em>

  1278. will be empty.  <em>sockaddr</em> is a tuple describing a socket address, whose

  1279. format depends on the returned <em>family</em> (a <code class="docutils literal notranslate"><span class="pre">(address,</span> <span class="pre">port)</span></code> 2-tuple for

  1280. <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a>, a <code class="docutils literal notranslate"><span class="pre">(address,</span> <span class="pre">port,</span> <span class="pre">flowinfo,</span> <span class="pre">scope_id)</span></code> 4-tuple for

  1281. <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>), and is meant to be passed to the <a class="reference internal" href="#socket.socket.connect" title="socket.socket.connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.connect()</span></code></a>

  1282. method.</p>

  1283. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.getaddrinfo</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">host</span></code>, <code class="docutils literal notranslate"><span class="pre">port</span></code>, <code class="docutils literal notranslate"><span class="pre">family</span></code>, <code class="docutils literal notranslate"><span class="pre">type</span></code>, <code class="docutils literal notranslate"><span class="pre">protocol</span></code>.</p>

  1284. <p>The following example fetches address information for a hypothetical TCP

  1285. connection to <code class="docutils literal notranslate"><span class="pre">example.org</span></code> on port 80 (results may differ on your

  1286. system if IPv6 isn’t enabled):</p>

  1287. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="n">socket</span><span class="o">.</span><span class="n">getaddrinfo</span><span class="p">(</span><span class="s2">&quot;example.org&quot;</span><span class="p">,</span> <span class="mi">80</span><span class="p">,</span> <span class="n">proto</span><span class="o">=</span><span class="n">socket</span><span class="o">.</span><span class="n">IPPROTO_TCP</span><span class="p">)</span>

  1288. <span class="go">[(socket.AF_INET6, socket.SOCK_STREAM,</span>

  1289. <span class="go"> 6, &#39;&#39;, (&#39;2606:2800:220:1:248:1893:25c8:1946&#39;, 80, 0, 0)),</span>

  1290. <span class="go"> (socket.AF_INET, socket.SOCK_STREAM,</span>

  1291. <span class="go"> 6, &#39;&#39;, (&#39;93.184.216.34&#39;, 80))]</span>

  1292. </pre></div>

  1293. </div>

  1294. <div class="versionchanged">

  1295. <p><span class="versionmodified changed">Changed in version 3.2: </span>parameters can now be passed using keyword arguments.</p>

  1296. </div>

  1297. <div class="versionchanged">

  1298. <p><span class="versionmodified changed">Changed in version 3.7: </span>for IPv6 multicast addresses, string representing an address will not

  1299. contain <code class="docutils literal notranslate"><span class="pre">%scope_id</span></code> part.</p>

  1300. </div>

  1301. </dd></dl>

  1302. 

  1303. <dl class="py function">

  1304. <dt class="sig sig-object py" id="socket.getfqdn">

  1305. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getfqdn</span></span><span class="sig-paren">(</span><span class="optional">[</span><em class="sig-param"><span class="n"><span class="pre">name</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.getfqdn" title="Link to this definition">¶</a></dt>

  1306. <dd><p>Return a fully qualified domain name for <em>name</em>. If <em>name</em> is omitted or empty,

  1307. it is interpreted as the local host.  To find the fully qualified name, the

  1308. hostname returned by <a class="reference internal" href="#socket.gethostbyaddr" title="socket.gethostbyaddr"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyaddr()</span></code></a> is checked, followed by aliases for the

  1309. host, if available.  The first name which includes a period is selected.  In

  1310. case no fully qualified domain name is available and <em>name</em> was provided,

  1311. it is returned unchanged.  If <em>name</em> was empty or equal to <code class="docutils literal notranslate"><span class="pre">'0.0.0.0'</span></code>,

  1312. the hostname from <a class="reference internal" href="#socket.gethostname" title="socket.gethostname"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostname()</span></code></a> is returned.</p>

  1313. </dd></dl>

  1314. 

  1315. <dl class="py function">

  1316. <dt class="sig sig-object py" id="socket.gethostbyname">

  1317. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gethostbyname</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">hostname</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.gethostbyname" title="Link to this definition">¶</a></dt>

  1318. <dd><p>Translate a host name to IPv4 address format.  The IPv4 address is returned as a

  1319. string, such as  <code class="docutils literal notranslate"><span class="pre">'100.50.200.5'</span></code>.  If the host name is an IPv4 address itself

  1320. it is returned unchanged.  See <a class="reference internal" href="#socket.gethostbyname_ex" title="socket.gethostbyname_ex"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyname_ex()</span></code></a> for a more complete

  1321. interface. <a class="reference internal" href="#socket.gethostbyname" title="socket.gethostbyname"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyname()</span></code></a> does not support IPv6 name resolution, and

  1322. <a class="reference internal" href="#socket.getaddrinfo" title="socket.getaddrinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getaddrinfo()</span></code></a> should be used instead for IPv4/v6 dual stack support.</p>

  1323. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.gethostbyname</span></code> with argument <code class="docutils literal notranslate"><span class="pre">hostname</span></code>.</p>

  1324. <div class="availability docutils container">

  1325. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1326. </div>

  1327. </dd></dl>

  1328. 

  1329. <dl class="py function">

  1330. <dt class="sig sig-object py" id="socket.gethostbyname_ex">

  1331. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gethostbyname_ex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">hostname</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.gethostbyname_ex" title="Link to this definition">¶</a></dt>

  1332. <dd><p>Translate a host name to IPv4 address format, extended interface. Return a

  1333. 3-tuple <code class="docutils literal notranslate"><span class="pre">(hostname,</span> <span class="pre">aliaslist,</span> <span class="pre">ipaddrlist)</span></code> where <em>hostname</em> is the host’s

  1334. primary host name, <em>aliaslist</em> is a (possibly

  1335. empty) list of alternative host names for the same address, and <em>ipaddrlist</em> is

  1336. a list of IPv4 addresses for the same interface on the same host (often but not

  1337. always a single address). <a class="reference internal" href="#socket.gethostbyname_ex" title="socket.gethostbyname_ex"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyname_ex()</span></code></a> does not support IPv6 name

  1338. resolution, and <a class="reference internal" href="#socket.getaddrinfo" title="socket.getaddrinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getaddrinfo()</span></code></a> should be used instead for IPv4/v6 dual

  1339. stack support.</p>

  1340. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.gethostbyname</span></code> with argument <code class="docutils literal notranslate"><span class="pre">hostname</span></code>.</p>

  1341. <div class="availability docutils container">

  1342. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1343. </div>

  1344. </dd></dl>

  1345. 

  1346. <dl class="py function">

  1347. <dt class="sig sig-object py" id="socket.gethostname">

  1348. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gethostname</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.gethostname" title="Link to this definition">¶</a></dt>

  1349. <dd><p>Return a string containing the hostname of the machine where  the Python

  1350. interpreter is currently executing.</p>

  1351. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.gethostname</span></code> with no arguments.</p>

  1352. <p>Note: <a class="reference internal" href="#socket.gethostname" title="socket.gethostname"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostname()</span></code></a> doesn’t always return the fully qualified domain

  1353. name; use <a class="reference internal" href="#socket.getfqdn" title="socket.getfqdn"><code class="xref py py-func docutils literal notranslate"><span class="pre">getfqdn()</span></code></a> for that.</p>

  1354. <div class="availability docutils container">

  1355. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1356. </div>

  1357. </dd></dl>

  1358. 

  1359. <dl class="py function">

  1360. <dt class="sig sig-object py" id="socket.gethostbyaddr">

  1361. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gethostbyaddr</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">ip_address</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.gethostbyaddr" title="Link to this definition">¶</a></dt>

  1362. <dd><p>Return a 3-tuple <code class="docutils literal notranslate"><span class="pre">(hostname,</span> <span class="pre">aliaslist,</span> <span class="pre">ipaddrlist)</span></code> where <em>hostname</em> is the

  1363. primary host name responding to the given <em>ip_address</em>, <em>aliaslist</em> is a

  1364. (possibly empty) list of alternative host names for the same address, and

  1365. <em>ipaddrlist</em> is a list of IPv4/v6 addresses for the same interface on the same

  1366. host (most likely containing only a single address). To find the fully qualified

  1367. domain name, use the function <a class="reference internal" href="#socket.getfqdn" title="socket.getfqdn"><code class="xref py py-func docutils literal notranslate"><span class="pre">getfqdn()</span></code></a>. <a class="reference internal" href="#socket.gethostbyaddr" title="socket.gethostbyaddr"><code class="xref py py-func docutils literal notranslate"><span class="pre">gethostbyaddr()</span></code></a> supports

  1368. both IPv4 and IPv6.</p>

  1369. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.gethostbyaddr</span></code> with argument <code class="docutils literal notranslate"><span class="pre">ip_address</span></code>.</p>

  1370. <div class="availability docutils container">

  1371. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1372. </div>

  1373. </dd></dl>

  1374. 

  1375. <dl class="py function">

  1376. <dt class="sig sig-object py" id="socket.getnameinfo">

  1377. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getnameinfo</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">sockaddr</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.getnameinfo" title="Link to this definition">¶</a></dt>

  1378. <dd><p>Translate a socket address <em>sockaddr</em> into a 2-tuple <code class="docutils literal notranslate"><span class="pre">(host,</span> <span class="pre">port)</span></code>. Depending

  1379. on the settings of <em>flags</em>, the result can contain a fully qualified domain name

  1380. or numeric address representation in <em>host</em>.  Similarly, <em>port</em> can contain a

  1381. string port name or a numeric port number.</p>

  1382. <p>For IPv6 addresses, <code class="docutils literal notranslate"><span class="pre">%scope_id</span></code> is appended to the host part if <em>sockaddr</em>

  1383. contains meaningful <em>scope_id</em>. Usually this happens for multicast addresses.</p>

  1384. <p>For more information about <em>flags</em> you can consult <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/getnameinfo(3)">getnameinfo(3)</a></em>.</p>

  1385. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.getnameinfo</span></code> with argument <code class="docutils literal notranslate"><span class="pre">sockaddr</span></code>.</p>

  1386. <div class="availability docutils container">

  1387. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1388. </div>

  1389. </dd></dl>

  1390. 

  1391. <dl class="py function">

  1392. <dt class="sig sig-object py" id="socket.getprotobyname">

  1393. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getprotobyname</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">protocolname</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.getprotobyname" title="Link to this definition">¶</a></dt>

  1394. <dd><p>Translate an internet protocol name (for example, <code class="docutils literal notranslate"><span class="pre">'icmp'</span></code>) to a constant

  1395. suitable for passing as the (optional) third argument to the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a>

  1396. function.  This is usually only needed for sockets opened in “raw” mode

  1397. (<a class="reference internal" href="#socket.SOCK_RAW" title="socket.SOCK_RAW"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_RAW</span></code></a>); for the normal socket modes, the correct protocol is chosen

  1398. automatically if the protocol is omitted or zero.</p>

  1399. <div class="availability docutils container">

  1400. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1401. </div>

  1402. </dd></dl>

  1403. 

  1404. <dl class="py function">

  1405. <dt class="sig sig-object py" id="socket.getservbyname">

  1406. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getservbyname</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">servicename</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">protocolname</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.getservbyname" title="Link to this definition">¶</a></dt>

  1407. <dd><p>Translate an internet service name and protocol name to a port number for that

  1408. service.  The optional protocol name, if given, should be <code class="docutils literal notranslate"><span class="pre">'tcp'</span></code> or

  1409. <code class="docutils literal notranslate"><span class="pre">'udp'</span></code>, otherwise any protocol will match.</p>

  1410. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.getservbyname</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">servicename</span></code>, <code class="docutils literal notranslate"><span class="pre">protocolname</span></code>.</p>

  1411. <div class="availability docutils container">

  1412. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1413. </div>

  1414. </dd></dl>

  1415. 

  1416. <dl class="py function">

  1417. <dt class="sig sig-object py" id="socket.getservbyport">

  1418. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getservbyport</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">port</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">protocolname</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.getservbyport" title="Link to this definition">¶</a></dt>

  1419. <dd><p>Translate an internet port number and protocol name to a service name for that

  1420. service.  The optional protocol name, if given, should be <code class="docutils literal notranslate"><span class="pre">'tcp'</span></code> or

  1421. <code class="docutils literal notranslate"><span class="pre">'udp'</span></code>, otherwise any protocol will match.</p>

  1422. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.getservbyport</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">port</span></code>, <code class="docutils literal notranslate"><span class="pre">protocolname</span></code>.</p>

  1423. <div class="availability docutils container">

  1424. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1425. </div>

  1426. </dd></dl>

  1427. 

  1428. <dl class="py function">

  1429. <dt class="sig sig-object py" id="socket.ntohl">

  1430. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ntohl</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">x</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.ntohl" title="Link to this definition">¶</a></dt>

  1431. <dd><p>Convert 32-bit positive integers from network to host byte order.  On machines

  1432. where the host byte order is the same as network byte order, this is a no-op;

  1433. otherwise, it performs a 4-byte swap operation.</p>

  1434. </dd></dl>

  1435. 

  1436. <dl class="py function">

  1437. <dt class="sig sig-object py" id="socket.ntohs">

  1438. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ntohs</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">x</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.ntohs" title="Link to this definition">¶</a></dt>

  1439. <dd><p>Convert 16-bit positive integers from network to host byte order.  On machines

  1440. where the host byte order is the same as network byte order, this is a no-op;

  1441. otherwise, it performs a 2-byte swap operation.</p>

  1442. <div class="versionchanged">

  1443. <p><span class="versionmodified changed">Changed in version 3.10: </span>Raises <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OverflowError</span></code></a> if <em>x</em> does not fit in a 16-bit unsigned

  1444. integer.</p>

  1445. </div>

  1446. </dd></dl>

  1447. 

  1448. <dl class="py function">

  1449. <dt class="sig sig-object py" id="socket.htonl">

  1450. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">htonl</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">x</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.htonl" title="Link to this definition">¶</a></dt>

  1451. <dd><p>Convert 32-bit positive integers from host to network byte order.  On machines

  1452. where the host byte order is the same as network byte order, this is a no-op;

  1453. otherwise, it performs a 4-byte swap operation.</p>

  1454. </dd></dl>

  1455. 

  1456. <dl class="py function">

  1457. <dt class="sig sig-object py" id="socket.htons">

  1458. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">htons</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">x</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.htons" title="Link to this definition">¶</a></dt>

  1459. <dd><p>Convert 16-bit positive integers from host to network byte order.  On machines

  1460. where the host byte order is the same as network byte order, this is a no-op;

  1461. otherwise, it performs a 2-byte swap operation.</p>

  1462. <div class="versionchanged">

  1463. <p><span class="versionmodified changed">Changed in version 3.10: </span>Raises <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OverflowError</span></code></a> if <em>x</em> does not fit in a 16-bit unsigned

  1464. integer.</p>

  1465. </div>

  1466. </dd></dl>

  1467. 

  1468. <dl class="py function">

  1469. <dt class="sig sig-object py" id="socket.inet_aton">

  1470. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">inet_aton</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">ip_string</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.inet_aton" title="Link to this definition">¶</a></dt>

  1471. <dd><p>Convert an IPv4 address from dotted-quad string format (for example,

  1472. ‘123.45.67.89’) to 32-bit packed binary format, as a bytes object four characters in

  1473. length.  This is useful when conversing with a program that uses the standard C

  1474. library and needs objects of type <code class="xref c c-struct docutils literal notranslate"><span class="pre">in_addr</span></code>, which is the C type

  1475. for the 32-bit packed binary this function returns.</p>

  1476. <p><a class="reference internal" href="#socket.inet_aton" title="socket.inet_aton"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_aton()</span></code></a> also accepts strings with less than three dots; see the

  1477. Unix manual page <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/inet(3)">inet(3)</a></em> for details.</p>

  1478. <p>If the IPv4 address string passed to this function is invalid,

  1479. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> will be raised. Note that exactly what is valid depends on

  1480. the underlying C implementation of <code class="xref c c-func docutils literal notranslate"><span class="pre">inet_aton()</span></code>.</p>

  1481. <p><a class="reference internal" href="#socket.inet_aton" title="socket.inet_aton"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_aton()</span></code></a> does not support IPv6, and <a class="reference internal" href="#socket.inet_pton" title="socket.inet_pton"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_pton()</span></code></a> should be used

  1482. instead for IPv4/v6 dual stack support.</p>

  1483. </dd></dl>

  1484. 

  1485. <dl class="py function">

  1486. <dt class="sig sig-object py" id="socket.inet_ntoa">

  1487. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">inet_ntoa</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">packed_ip</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.inet_ntoa" title="Link to this definition">¶</a></dt>

  1488. <dd><p>Convert a 32-bit packed IPv4 address (a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> four

  1489. bytes in length) to its standard dotted-quad string representation (for example,

  1490. ‘123.45.67.89’).  This is useful when conversing with a program that uses the

  1491. standard C library and needs objects of type <code class="xref c c-struct docutils literal notranslate"><span class="pre">in_addr</span></code>, which

  1492. is the C type for the 32-bit packed binary data this function takes as an

  1493. argument.</p>

  1494. <p>If the byte sequence passed to this function is not exactly 4 bytes in

  1495. length, <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> will be raised. <a class="reference internal" href="#socket.inet_ntoa" title="socket.inet_ntoa"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_ntoa()</span></code></a> does not

  1496. support IPv6, and <a class="reference internal" href="#socket.inet_ntop" title="socket.inet_ntop"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_ntop()</span></code></a> should be used instead for IPv4/v6 dual

  1497. stack support.</p>

  1498. <div class="versionchanged">

  1499. <p><span class="versionmodified changed">Changed in version 3.5: </span>Writable <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> is now accepted.</p>

  1500. </div>

  1501. </dd></dl>

  1502. 

  1503. <dl class="py function">

  1504. <dt class="sig sig-object py" id="socket.inet_pton">

  1505. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">inet_pton</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address_family</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">ip_string</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.inet_pton" title="Link to this definition">¶</a></dt>

  1506. <dd><p>Convert an IP address from its family-specific string format to a packed,

  1507. binary format. <a class="reference internal" href="#socket.inet_pton" title="socket.inet_pton"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_pton()</span></code></a> is useful when a library or network protocol

  1508. calls for an object of type <code class="xref c c-struct docutils literal notranslate"><span class="pre">in_addr</span></code> (similar to

  1509. <a class="reference internal" href="#socket.inet_aton" title="socket.inet_aton"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_aton()</span></code></a>) or <code class="xref c c-struct docutils literal notranslate"><span class="pre">in6_addr</span></code>.</p>

  1510. <p>Supported values for <em>address_family</em> are currently <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a> and

  1511. <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>. If the IP address string <em>ip_string</em> is invalid,

  1512. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> will be raised. Note that exactly what is valid depends on

  1513. both the value of <em>address_family</em> and the underlying implementation of

  1514. <code class="xref c c-func docutils literal notranslate"><span class="pre">inet_pton()</span></code>.</p>

  1515. <div class="availability docutils container">

  1516. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows.</p>

  1517. </div>

  1518. <div class="versionchanged">

  1519. <p><span class="versionmodified changed">Changed in version 3.4: </span>Windows support added</p>

  1520. </div>

  1521. </dd></dl>

  1522. 

  1523. <dl class="py function">

  1524. <dt class="sig sig-object py" id="socket.inet_ntop">

  1525. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">inet_ntop</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address_family</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">packed_ip</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.inet_ntop" title="Link to this definition">¶</a></dt>

  1526. <dd><p>Convert a packed IP address (a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> of some number of

  1527. bytes) to its standard, family-specific string representation (for

  1528. example, <code class="docutils literal notranslate"><span class="pre">'7.10.0.5'</span></code> or <code class="docutils literal notranslate"><span class="pre">'5aef:2b::8'</span></code>).

  1529. <a class="reference internal" href="#socket.inet_ntop" title="socket.inet_ntop"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_ntop()</span></code></a> is useful when a library or network protocol returns an

  1530. object of type <code class="xref c c-struct docutils literal notranslate"><span class="pre">in_addr</span></code> (similar to <a class="reference internal" href="#socket.inet_ntoa" title="socket.inet_ntoa"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_ntoa()</span></code></a>) or

  1531. <code class="xref c c-struct docutils literal notranslate"><span class="pre">in6_addr</span></code>.</p>

  1532. <p>Supported values for <em>address_family</em> are currently <a class="reference internal" href="#socket.AF_INET" title="socket.AF_INET"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET</span></code></a> and

  1533. <a class="reference internal" href="#socket.AF_INET6" title="socket.AF_INET6"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_INET6</span></code></a>. If the bytes object <em>packed_ip</em> is not the correct

  1534. length for the specified address family, <a class="reference internal" href="exceptions.html#ValueError" title="ValueError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">ValueError</span></code></a> will be raised.

  1535. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> is raised for errors from the call to <a class="reference internal" href="#socket.inet_ntop" title="socket.inet_ntop"><code class="xref py py-func docutils literal notranslate"><span class="pre">inet_ntop()</span></code></a>.</p>

  1536. <div class="availability docutils container">

  1537. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows.</p>

  1538. </div>

  1539. <div class="versionchanged">

  1540. <p><span class="versionmodified changed">Changed in version 3.4: </span>Windows support added</p>

  1541. </div>

  1542. <div class="versionchanged">

  1543. <p><span class="versionmodified changed">Changed in version 3.5: </span>Writable <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> is now accepted.</p>

  1544. </div>

  1545. </dd></dl>

  1546. 

  1547. <dl class="py function">

  1548. <dt class="sig sig-object py" id="socket.CMSG_LEN">

  1549. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CMSG_LEN</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">length</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.CMSG_LEN" title="Link to this definition">¶</a></dt>

  1550. <dd><p>Return the total length, without trailing padding, of an ancillary

  1551. data item with associated data of the given <em>length</em>.  This value

  1552. can often be used as the buffer size for <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> to

  1553. receive a single item of ancillary data, but <span class="target" id="index-3"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc3542.html"><strong>RFC 3542</strong></a> requires

  1554. portable applications to use <a class="reference internal" href="#socket.CMSG_SPACE" title="socket.CMSG_SPACE"><code class="xref py py-func docutils literal notranslate"><span class="pre">CMSG_SPACE()</span></code></a> and thus include

  1555. space for padding, even when the item will be the last in the

  1556. buffer.  Raises <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OverflowError</span></code></a> if <em>length</em> is outside the

  1557. permissible range of values.</p>

  1558. <div class="availability docutils container">

  1559. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, not Emscripten, not WASI.</p>

  1560. <p>Most Unix platforms.</p>

  1561. </div>

  1562. <div class="versionadded">

  1563. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1564. </div>

  1565. </dd></dl>

  1566. 

  1567. <dl class="py function">

  1568. <dt class="sig sig-object py" id="socket.CMSG_SPACE">

  1569. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">CMSG_SPACE</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">length</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.CMSG_SPACE" title="Link to this definition">¶</a></dt>

  1570. <dd><p>Return the buffer size needed for <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> to

  1571. receive an ancillary data item with associated data of the given

  1572. <em>length</em>, along with any trailing padding.  The buffer space needed

  1573. to receive multiple items is the sum of the <a class="reference internal" href="#socket.CMSG_SPACE" title="socket.CMSG_SPACE"><code class="xref py py-func docutils literal notranslate"><span class="pre">CMSG_SPACE()</span></code></a>

  1574. values for their associated data lengths.  Raises

  1575. <a class="reference internal" href="exceptions.html#OverflowError" title="OverflowError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OverflowError</span></code></a> if <em>length</em> is outside the permissible range

  1576. of values.</p>

  1577. <p>Note that some systems might support ancillary data without

  1578. providing this function.  Also note that setting the buffer size

  1579. using the results of this function may not precisely limit the

  1580. amount of ancillary data that can be received, since additional

  1581. data may be able to fit into the padding area.</p>

  1582. <div class="availability docutils container">

  1583. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, not Emscripten, not WASI.</p>

  1584. <p>most Unix platforms.</p>

  1585. </div>

  1586. <div class="versionadded">

  1587. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1588. </div>

  1589. </dd></dl>

  1590. 

  1591. <dl class="py function">

  1592. <dt class="sig sig-object py" id="socket.getdefaulttimeout">

  1593. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getdefaulttimeout</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.getdefaulttimeout" title="Link to this definition">¶</a></dt>

  1594. <dd><p>Return the default timeout in seconds (float) for new socket objects. A value

  1595. of <code class="docutils literal notranslate"><span class="pre">None</span></code> indicates that new socket objects have no timeout. When the socket

  1596. module is first imported, the default is <code class="docutils literal notranslate"><span class="pre">None</span></code>.</p>

  1597. </dd></dl>

  1598. 

  1599. <dl class="py function">

  1600. <dt class="sig sig-object py" id="socket.setdefaulttimeout">

  1601. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">setdefaulttimeout</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">timeout</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.setdefaulttimeout" title="Link to this definition">¶</a></dt>

  1602. <dd><p>Set the default timeout in seconds (float) for new socket objects.  When

  1603. the socket module is first imported, the default is <code class="docutils literal notranslate"><span class="pre">None</span></code>.  See

  1604. <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a> for possible values and their respective

  1605. meanings.</p>

  1606. </dd></dl>

  1607. 

  1608. <dl class="py function">

  1609. <dt class="sig sig-object py" id="socket.sethostname">

  1610. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sethostname</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">name</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.sethostname" title="Link to this definition">¶</a></dt>

  1611. <dd><p>Set the machine’s hostname to <em>name</em>.  This will raise an

  1612. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> if you don’t have enough rights.</p>

  1613. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.sethostname</span></code> with argument <code class="docutils literal notranslate"><span class="pre">name</span></code>.</p>

  1614. <div class="availability docutils container">

  1615. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix.</p>

  1616. </div>

  1617. <div class="versionadded">

  1618. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1619. </div>

  1620. </dd></dl>

  1621. 

  1622. <dl class="py function">

  1623. <dt class="sig sig-object py" id="socket.if_nameindex">

  1624. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">if_nameindex</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.if_nameindex" title="Link to this definition">¶</a></dt>

  1625. <dd><p>Return a list of network interface information

  1626. (index int, name string) tuples.

  1627. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> if the system call fails.</p>

  1628. <div class="availability docutils container">

  1629. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows, not Emscripten, not WASI.</p>

  1630. </div>

  1631. <div class="versionadded">

  1632. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1633. </div>

  1634. <div class="versionchanged">

  1635. <p><span class="versionmodified changed">Changed in version 3.8: </span>Windows support was added.</p>

  1636. </div>

  1637. <div class="admonition note">

  1638. <p class="admonition-title">Note</p>

  1639. <p>On Windows network interfaces have different names in different contexts

  1640. (all names are examples):</p>

  1641. <ul class="simple">

  1642. <li><p>UUID: <code class="docutils literal notranslate"><span class="pre">{FB605B73-AAC2-49A6-9A2F-25416AEA0573}</span></code></p></li>

  1643. <li><p>name: <code class="docutils literal notranslate"><span class="pre">ethernet_32770</span></code></p></li>

  1644. <li><p>friendly name: <code class="docutils literal notranslate"><span class="pre">vEthernet</span> <span class="pre">(nat)</span></code></p></li>

  1645. <li><p>description: <code class="docutils literal notranslate"><span class="pre">Hyper-V</span> <span class="pre">Virtual</span> <span class="pre">Ethernet</span> <span class="pre">Adapter</span></code></p></li>

  1646. </ul>

  1647. <p>This function returns names of the second form from the list, <code class="docutils literal notranslate"><span class="pre">ethernet_32770</span></code>

  1648. in this example case.</p>

  1649. </div>

  1650. </dd></dl>

  1651. 

  1652. <dl class="py function">

  1653. <dt class="sig sig-object py" id="socket.if_nametoindex">

  1654. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">if_nametoindex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">if_name</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.if_nametoindex" title="Link to this definition">¶</a></dt>

  1655. <dd><p>Return a network interface index number corresponding to an

  1656. interface name.

  1657. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> if no interface with the given name exists.</p>

  1658. <div class="availability docutils container">

  1659. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows, not Emscripten, not WASI.</p>

  1660. </div>

  1661. <div class="versionadded">

  1662. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1663. </div>

  1664. <div class="versionchanged">

  1665. <p><span class="versionmodified changed">Changed in version 3.8: </span>Windows support was added.</p>

  1666. </div>

  1667. <div class="admonition seealso">

  1668. <p class="admonition-title">See also</p>

  1669. <p>“Interface name” is a name as documented in <a class="reference internal" href="#socket.if_nameindex" title="socket.if_nameindex"><code class="xref py py-func docutils literal notranslate"><span class="pre">if_nameindex()</span></code></a>.</p>

  1670. </div>

  1671. </dd></dl>

  1672. 

  1673. <dl class="py function">

  1674. <dt class="sig sig-object py" id="socket.if_indextoname">

  1675. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">if_indextoname</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">if_index</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.if_indextoname" title="Link to this definition">¶</a></dt>

  1676. <dd><p>Return a network interface name corresponding to an

  1677. interface index number.

  1678. <a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> if no interface with the given index exists.</p>

  1679. <div class="availability docutils container">

  1680. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows, not Emscripten, not WASI.</p>

  1681. </div>

  1682. <div class="versionadded">

  1683. <p><span class="versionmodified added">New in version 3.3.</span></p>

  1684. </div>

  1685. <div class="versionchanged">

  1686. <p><span class="versionmodified changed">Changed in version 3.8: </span>Windows support was added.</p>

  1687. </div>

  1688. <div class="admonition seealso">

  1689. <p class="admonition-title">See also</p>

  1690. <p>“Interface name” is a name as documented in <a class="reference internal" href="#socket.if_nameindex" title="socket.if_nameindex"><code class="xref py py-func docutils literal notranslate"><span class="pre">if_nameindex()</span></code></a>.</p>

  1691. </div>

  1692. </dd></dl>

  1693. 

  1694. <dl class="py function">

  1695. <dt class="sig sig-object py" id="socket.send_fds">

  1696. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">send_fds</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">sock</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">buffers</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">fds</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.send_fds" title="Link to this definition">¶</a></dt>

  1697. <dd><p>Send the list of file descriptors <em>fds</em> over an <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> socket <em>sock</em>.

  1698. The <em>fds</em> parameter is a sequence of file descriptors.

  1699. Consult <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a> for the documentation of these parameters.</p>

  1700. <div class="availability docutils container">

  1701. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows, not Emscripten, not WASI.</p>

  1702. <p>Unix platforms supporting <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a>

  1703. and <code class="xref py py-const docutils literal notranslate"><span class="pre">SCM_RIGHTS</span></code> mechanism.</p>

  1704. </div>

  1705. <div class="versionadded">

  1706. <p><span class="versionmodified added">New in version 3.9.</span></p>

  1707. </div>

  1708. </dd></dl>

  1709. 

  1710. <dl class="py function">

  1711. <dt class="sig sig-object py" id="socket.recv_fds">

  1712. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recv_fds</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">sock</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">bufsize</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">maxfds</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.recv_fds" title="Link to this definition">¶</a></dt>

  1713. <dd><p>Receive up to <em>maxfds</em> file descriptors from an <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> socket <em>sock</em>.

  1714. Return <code class="docutils literal notranslate"><span class="pre">(msg,</span> <span class="pre">list(fds),</span> <span class="pre">flags,</span> <span class="pre">addr)</span></code>.

  1715. Consult <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> for the documentation of these parameters.</p>

  1716. <div class="availability docutils container">

  1717. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, Windows, not Emscripten, not WASI.</p>

  1718. <p>Unix platforms supporting <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a>

  1719. and <code class="xref py py-const docutils literal notranslate"><span class="pre">SCM_RIGHTS</span></code> mechanism.</p>

  1720. </div>

  1721. <div class="versionadded">

  1722. <p><span class="versionmodified added">New in version 3.9.</span></p>

  1723. </div>

  1724. <div class="admonition note">

  1725. <p class="admonition-title">Note</p>

  1726. <p>Any truncated integers at the end of the list of file descriptors.</p>

  1727. </div>

  1728. </dd></dl>

  1729. 

  1730. </section>

  1731. </section>

  1732. </section>

  1733. <section id="socket-objects">

  1734. <span id="id1"></span><h2>Socket Objects<a class="headerlink" href="#socket-objects" title="Link to this heading">¶</a></h2>

  1735. <p>Socket objects have the following methods.  Except for

  1736. <a class="reference internal" href="#socket.socket.makefile" title="socket.socket.makefile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makefile()</span></code></a>, these correspond to Unix system calls applicable

  1737. to sockets.</p>

  1738. <div class="versionchanged">

  1739. <p><span class="versionmodified changed">Changed in version 3.2: </span>Support for the <a class="reference internal" href="../glossary.html#term-context-manager"><span class="xref std std-term">context manager</span></a> protocol was added.  Exiting the

  1740. context manager is equivalent to calling <a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a>.</p>

  1741. </div>

  1742. <dl class="py method">

  1743. <dt class="sig sig-object py" id="socket.socket.accept">

  1744. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">accept</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.accept" title="Link to this definition">¶</a></dt>

  1745. <dd><p>Accept a connection. The socket must be bound to an address and listening for

  1746. connections. The return value is a pair <code class="docutils literal notranslate"><span class="pre">(conn,</span> <span class="pre">address)</span></code> where <em>conn</em> is a

  1747. <em>new</em> socket object usable to send and receive data on the connection, and

  1748. <em>address</em> is the address bound to the socket on the other end of the connection.</p>

  1749. <p>The newly created socket is <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">non-inheritable</span></a>.</p>

  1750. <div class="versionchanged">

  1751. <p><span class="versionmodified changed">Changed in version 3.4: </span>The socket is now non-inheritable.</p>

  1752. </div>

  1753. <div class="versionchanged">

  1754. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  1755. an exception, the method now retries the system call instead of raising

  1756. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-4"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  1757. </div>

  1758. </dd></dl>

  1759. 

  1760. <dl class="py method">

  1761. <dt class="sig sig-object py" id="socket.socket.bind">

  1762. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">bind</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.bind" title="Link to this definition">¶</a></dt>

  1763. <dd><p>Bind the socket to <em>address</em>.  The socket must not already be bound. (The format

  1764. of <em>address</em> depends on the address family — see above.)</p>

  1765. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.bind</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">address</span></code>.</p>

  1766. <div class="availability docutils container">

  1767. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1768. </div>

  1769. </dd></dl>

  1770. 

  1771. <dl class="py method">

  1772. <dt class="sig sig-object py" id="socket.socket.close">

  1773. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">close</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.close" title="Link to this definition">¶</a></dt>

  1774. <dd><p>Mark the socket closed.  The underlying system resource (e.g. a file

  1775. descriptor) is also closed when all file objects from <a class="reference internal" href="#socket.socket.makefile" title="socket.socket.makefile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makefile()</span></code></a>

  1776. are closed.  Once that happens, all future operations on the socket

  1777. object will fail. The remote end will receive no more data (after

  1778. queued data is flushed).</p>

  1779. <p>Sockets are automatically closed when they are garbage-collected, but

  1780. it is recommended to <a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> them explicitly, or to use a

  1781. <a class="reference internal" href="../reference/compound_stmts.html#with"><code class="xref std std-keyword docutils literal notranslate"><span class="pre">with</span></code></a> statement around them.</p>

  1782. <div class="versionchanged">

  1783. <p><span class="versionmodified changed">Changed in version 3.6: </span><a class="reference internal" href="exceptions.html#OSError" title="OSError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">OSError</span></code></a> is now raised if an error occurs when the underlying

  1784. <code class="xref c c-func docutils literal notranslate"><span class="pre">close()</span></code> call is made.</p>

  1785. </div>

  1786. <div class="admonition note">

  1787. <p class="admonition-title">Note</p>

  1788. <p><a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a> releases the resource associated with a connection but

  1789. does not necessarily close the connection immediately.  If you want

  1790. to close the connection in a timely fashion, call <a class="reference internal" href="#socket.socket.shutdown" title="socket.socket.shutdown"><code class="xref py py-meth docutils literal notranslate"><span class="pre">shutdown()</span></code></a>

  1791. before <a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">close()</span></code></a>.</p>

  1792. </div>

  1793. </dd></dl>

  1794. 

  1795. <dl class="py method">

  1796. <dt class="sig sig-object py" id="socket.socket.connect">

  1797. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">connect</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.connect" title="Link to this definition">¶</a></dt>

  1798. <dd><p>Connect to a remote socket at <em>address</em>. (The format of <em>address</em> depends on the

  1799. address family — see above.)</p>

  1800. <p>If the connection is interrupted by a signal, the method waits until the

  1801. connection completes, or raise a <a class="reference internal" href="exceptions.html#TimeoutError" title="TimeoutError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">TimeoutError</span></code></a> on timeout, if the

  1802. signal handler doesn’t raise an exception and the socket is blocking or has

  1803. a timeout. For non-blocking sockets, the method raises an

  1804. <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception if the connection is interrupted by a

  1805. signal (or the exception raised by the signal handler).</p>

  1806. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.connect</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">address</span></code>.</p>

  1807. <div class="versionchanged">

  1808. <p><span class="versionmodified changed">Changed in version 3.5: </span>The method now waits until the connection completes instead of raising an

  1809. <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception if the connection is interrupted by a

  1810. signal, the signal handler doesn’t raise an exception and the socket is

  1811. blocking or has a timeout (see the <span class="target" id="index-5"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  1812. </div>

  1813. <div class="availability docutils container">

  1814. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1815. </div>

  1816. </dd></dl>

  1817. 

  1818. <dl class="py method">

  1819. <dt class="sig sig-object py" id="socket.socket.connect_ex">

  1820. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">connect_ex</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.connect_ex" title="Link to this definition">¶</a></dt>

  1821. <dd><p>Like <code class="docutils literal notranslate"><span class="pre">connect(address)</span></code>, but return an error indicator instead of raising an

  1822. exception for errors returned by the C-level <code class="xref c c-func docutils literal notranslate"><span class="pre">connect()</span></code> call (other

  1823. problems, such as “host not found,” can still raise exceptions).  The error

  1824. indicator is <code class="docutils literal notranslate"><span class="pre">0</span></code> if the operation succeeded, otherwise the value of the

  1825. <code class="xref c c-data docutils literal notranslate"><span class="pre">errno</span></code> variable.  This is useful to support, for example, asynchronous

  1826. connects.</p>

  1827. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.connect</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">address</span></code>.</p>

  1828. <div class="availability docutils container">

  1829. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1830. </div>

  1831. </dd></dl>

  1832. 

  1833. <dl class="py method">

  1834. <dt class="sig sig-object py" id="socket.socket.detach">

  1835. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">detach</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.detach" title="Link to this definition">¶</a></dt>

  1836. <dd><p>Put the socket object into closed state without actually closing the

  1837. underlying file descriptor.  The file descriptor is returned, and can

  1838. be reused for other purposes.</p>

  1839. <div class="versionadded">

  1840. <p><span class="versionmodified added">New in version 3.2.</span></p>

  1841. </div>

  1842. </dd></dl>

  1843. 

  1844. <dl class="py method">

  1845. <dt class="sig sig-object py" id="socket.socket.dup">

  1846. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">dup</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.dup" title="Link to this definition">¶</a></dt>

  1847. <dd><p>Duplicate the socket.</p>

  1848. <p>The newly created socket is <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">non-inheritable</span></a>.</p>

  1849. <div class="versionchanged">

  1850. <p><span class="versionmodified changed">Changed in version 3.4: </span>The socket is now non-inheritable.</p>

  1851. </div>

  1852. <div class="availability docutils container">

  1853. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1854. </div>

  1855. </dd></dl>

  1856. 

  1857. <dl class="py method">

  1858. <dt class="sig sig-object py" id="socket.socket.fileno">

  1859. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">fileno</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.fileno" title="Link to this definition">¶</a></dt>

  1860. <dd><p>Return the socket’s file descriptor (a small integer), or -1 on failure. This

  1861. is useful with <a class="reference internal" href="select.html#select.select" title="select.select"><code class="xref py py-func docutils literal notranslate"><span class="pre">select.select()</span></code></a>.</p>

  1862. <p>Under Windows the small integer returned by this method cannot be used where a

  1863. file descriptor can be used (such as <a class="reference internal" href="os.html#os.fdopen" title="os.fdopen"><code class="xref py py-func docutils literal notranslate"><span class="pre">os.fdopen()</span></code></a>).  Unix does not have

  1864. this limitation.</p>

  1865. </dd></dl>

  1866. 

  1867. <dl class="py method">

  1868. <dt class="sig sig-object py" id="socket.socket.get_inheritable">

  1869. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">get_inheritable</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.get_inheritable" title="Link to this definition">¶</a></dt>

  1870. <dd><p>Get the <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">inheritable flag</span></a> of the socket’s file

  1871. descriptor or socket’s handle: <code class="docutils literal notranslate"><span class="pre">True</span></code> if the socket can be inherited in

  1872. child processes, <code class="docutils literal notranslate"><span class="pre">False</span></code> if it cannot.</p>

  1873. <div class="versionadded">

  1874. <p><span class="versionmodified added">New in version 3.4.</span></p>

  1875. </div>

  1876. </dd></dl>

  1877. 

  1878. <dl class="py method">

  1879. <dt class="sig sig-object py" id="socket.socket.getpeername">

  1880. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getpeername</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.getpeername" title="Link to this definition">¶</a></dt>

  1881. <dd><p>Return the remote address to which the socket is connected.  This is useful to

  1882. find out the port number of a remote IPv4/v6 socket, for instance. (The format

  1883. of the address returned depends on the address family — see above.)  On some

  1884. systems this function is not supported.</p>

  1885. </dd></dl>

  1886. 

  1887. <dl class="py method">

  1888. <dt class="sig sig-object py" id="socket.socket.getsockname">

  1889. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getsockname</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.getsockname" title="Link to this definition">¶</a></dt>

  1890. <dd><p>Return the socket’s own address.  This is useful to find out the port number of

  1891. an IPv4/v6 socket, for instance. (The format of the address returned depends on

  1892. the address family — see above.)</p>

  1893. </dd></dl>

  1894. 

  1895. <dl class="py method">

  1896. <dt class="sig sig-object py" id="socket.socket.getsockopt">

  1897. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getsockopt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">optname</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">buflen</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.getsockopt" title="Link to this definition">¶</a></dt>

  1898. <dd><p>Return the value of the given socket option (see the Unix man page

  1899. <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/getsockopt(2)">getsockopt(2)</a></em>).  The needed symbolic constants (<a class="reference internal" href="#socket-unix-constants"><span class="std std-ref">SO_* etc.</span></a>)

  1900. are defined in this module.  If <em>buflen</em> is absent, an integer option is assumed

  1901. and its integer value is returned by the function.  If <em>buflen</em> is present, it

  1902. specifies the maximum length of the buffer used to receive the option in, and

  1903. this buffer is returned as a bytes object.  It is up to the caller to decode the

  1904. contents of the buffer (see the optional built-in module <a class="reference internal" href="struct.html#module-struct" title="struct: Interpret bytes as packed binary data."><code class="xref py py-mod docutils literal notranslate"><span class="pre">struct</span></code></a> for a way

  1905. to decode C structures encoded as byte strings).</p>

  1906. <div class="availability docutils container">

  1907. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1908. </div>

  1909. </dd></dl>

  1910. 

  1911. <dl class="py method">

  1912. <dt class="sig sig-object py" id="socket.socket.getblocking">

  1913. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">getblocking</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.getblocking" title="Link to this definition">¶</a></dt>

  1914. <dd><p>Return <code class="docutils literal notranslate"><span class="pre">True</span></code> if socket is in blocking mode, <code class="docutils literal notranslate"><span class="pre">False</span></code> if in

  1915. non-blocking.</p>

  1916. <p>This is equivalent to checking <code class="docutils literal notranslate"><span class="pre">socket.gettimeout()</span> <span class="pre">!=</span> <span class="pre">0</span></code>.</p>

  1917. <div class="versionadded">

  1918. <p><span class="versionmodified added">New in version 3.7.</span></p>

  1919. </div>

  1920. </dd></dl>

  1921. 

  1922. <dl class="py method">

  1923. <dt class="sig sig-object py" id="socket.socket.gettimeout">

  1924. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">gettimeout</span></span><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.gettimeout" title="Link to this definition">¶</a></dt>

  1925. <dd><p>Return the timeout in seconds (float) associated with socket operations,

  1926. or <code class="docutils literal notranslate"><span class="pre">None</span></code> if no timeout is set.  This reflects the last call to

  1927. <a class="reference internal" href="#socket.socket.setblocking" title="socket.socket.setblocking"><code class="xref py py-meth docutils literal notranslate"><span class="pre">setblocking()</span></code></a> or <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a>.</p>

  1928. </dd></dl>

  1929. 

  1930. <dl class="py method">

  1931. <dt class="sig sig-object py" id="socket.socket.ioctl">

  1932. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">ioctl</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">control</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">option</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.ioctl" title="Link to this definition">¶</a></dt>

  1933. <dd><dl class="field-list simple">

  1934. <dt class="field-odd">Platform<span class="colon">:</span></dt>

  1935. <dd class="field-odd"><p>Windows</p>

  1936. </dd>

  1937. </dl>

  1938. <p>The <a class="reference internal" href="#socket.socket.ioctl" title="socket.socket.ioctl"><code class="xref py py-meth docutils literal notranslate"><span class="pre">ioctl()</span></code></a> method is a limited interface to the WSAIoctl system

  1939. interface.  Please refer to the <a class="reference external" href="https://msdn.microsoft.com/en-us/library/ms741621%28VS.85%29.aspx">Win32 documentation</a> for more

  1940. information.</p>

  1941. <p>On other platforms, the generic <a class="reference internal" href="fcntl.html#fcntl.fcntl" title="fcntl.fcntl"><code class="xref py py-func docutils literal notranslate"><span class="pre">fcntl.fcntl()</span></code></a> and <a class="reference internal" href="fcntl.html#fcntl.ioctl" title="fcntl.ioctl"><code class="xref py py-func docutils literal notranslate"><span class="pre">fcntl.ioctl()</span></code></a>

  1942. functions may be used; they accept a socket object as their first argument.</p>

  1943. <p>Currently only the following control codes are supported:

  1944. <code class="docutils literal notranslate"><span class="pre">SIO_RCVALL</span></code>, <code class="docutils literal notranslate"><span class="pre">SIO_KEEPALIVE_VALS</span></code>, and <code class="docutils literal notranslate"><span class="pre">SIO_LOOPBACK_FAST_PATH</span></code>.</p>

  1945. <div class="versionchanged">

  1946. <p><span class="versionmodified changed">Changed in version 3.6: </span><code class="docutils literal notranslate"><span class="pre">SIO_LOOPBACK_FAST_PATH</span></code> was added.</p>

  1947. </div>

  1948. </dd></dl>

  1949. 

  1950. <dl class="py method">

  1951. <dt class="sig sig-object py" id="socket.socket.listen">

  1952. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">listen</span></span><span class="sig-paren">(</span><span class="optional">[</span><em class="sig-param"><span class="n"><span class="pre">backlog</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.listen" title="Link to this definition">¶</a></dt>

  1953. <dd><p>Enable a server to accept connections.  If <em>backlog</em> is specified, it must

  1954. be at least 0 (if it is lower, it is set to 0); it specifies the number of

  1955. unaccepted connections that the system will allow before refusing new

  1956. connections. If not specified, a default reasonable value is chosen.</p>

  1957. <div class="availability docutils container">

  1958. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  1959. </div>

  1960. <div class="versionchanged">

  1961. <p><span class="versionmodified changed">Changed in version 3.5: </span>The <em>backlog</em> parameter is now optional.</p>

  1962. </div>

  1963. </dd></dl>

  1964. 

  1965. <dl class="py method">

  1966. <dt class="sig sig-object py" id="socket.socket.makefile">

  1967. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">makefile</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">mode</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">'r'</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">buffering</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="o"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">encoding</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">errors</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">newline</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.makefile" title="Link to this definition">¶</a></dt>

  1968. <dd><p id="index-6">Return a <a class="reference internal" href="../glossary.html#term-file-object"><span class="xref std std-term">file object</span></a> associated with the socket.  The exact returned

  1969. type depends on the arguments given to <a class="reference internal" href="#socket.socket.makefile" title="socket.socket.makefile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makefile()</span></code></a>.  These arguments are

  1970. interpreted the same way as by the built-in <a class="reference internal" href="functions.html#open" title="open"><code class="xref py py-func docutils literal notranslate"><span class="pre">open()</span></code></a> function, except

  1971. the only supported <em>mode</em> values are <code class="docutils literal notranslate"><span class="pre">'r'</span></code> (default), <code class="docutils literal notranslate"><span class="pre">'w'</span></code> and <code class="docutils literal notranslate"><span class="pre">'b'</span></code>.</p>

  1972. <p>The socket must be in blocking mode; it can have a timeout, but the file

  1973. object’s internal buffer may end up in an inconsistent state if a timeout

  1974. occurs.</p>

  1975. <p>Closing the file object returned by <a class="reference internal" href="#socket.socket.makefile" title="socket.socket.makefile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makefile()</span></code></a> won’t close the

  1976. original socket unless all other file objects have been closed and

  1977. <a class="reference internal" href="#socket.close" title="socket.close"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.close()</span></code></a> has been called on the socket object.</p>

  1978. <div class="admonition note">

  1979. <p class="admonition-title">Note</p>

  1980. <p>On Windows, the file-like object created by <a class="reference internal" href="#socket.socket.makefile" title="socket.socket.makefile"><code class="xref py py-meth docutils literal notranslate"><span class="pre">makefile()</span></code></a> cannot be

  1981. used where a file object with a file descriptor is expected, such as the

  1982. stream arguments of <a class="reference internal" href="subprocess.html#subprocess.Popen" title="subprocess.Popen"><code class="xref py py-meth docutils literal notranslate"><span class="pre">subprocess.Popen()</span></code></a>.</p>

  1983. </div>

  1984. </dd></dl>

  1985. 

  1986. <dl class="py method">

  1987. <dt class="sig sig-object py" id="socket.socket.recv">

  1988. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recv</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bufsize</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recv" title="Link to this definition">¶</a></dt>

  1989. <dd><p>Receive data from the socket.  The return value is a bytes object representing the

  1990. data received.  The maximum amount of data to be received at once is specified

  1991. by <em>bufsize</em>. A returned empty bytes object indicates that the client has disconnected.

  1992. See the Unix manual page <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/recv(2)">recv(2)</a></em> for the meaning of the optional argument

  1993. <em>flags</em>; it defaults to zero.</p>

  1994. <div class="admonition note">

  1995. <p class="admonition-title">Note</p>

  1996. <p>For best match with hardware and network realities, the value of  <em>bufsize</em>

  1997. should be a relatively small power of 2, for example, 4096.</p>

  1998. </div>

  1999. <div class="versionchanged">

  2000. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2001. an exception, the method now retries the system call instead of raising

  2002. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-7"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2003. </div>

  2004. </dd></dl>

  2005. 

  2006. <dl class="py method">

  2007. <dt class="sig sig-object py" id="socket.socket.recvfrom">

  2008. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recvfrom</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bufsize</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recvfrom" title="Link to this definition">¶</a></dt>

  2009. <dd><p>Receive data from the socket.  The return value is a pair <code class="docutils literal notranslate"><span class="pre">(bytes,</span> <span class="pre">address)</span></code>

  2010. where <em>bytes</em> is a bytes object representing the data received and <em>address</em> is the

  2011. address of the socket sending the data.  See the Unix manual page

  2012. <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/recv(2)">recv(2)</a></em> for the meaning of the optional argument <em>flags</em>; it defaults

  2013. to zero. (The format of <em>address</em> depends on the address family — see above.)</p>

  2014. <div class="versionchanged">

  2015. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2016. an exception, the method now retries the system call instead of raising

  2017. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-8"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2018. </div>

  2019. <div class="versionchanged">

  2020. <p><span class="versionmodified changed">Changed in version 3.7: </span>For multicast IPv6 address, first item of <em>address</em> does not contain

  2021. <code class="docutils literal notranslate"><span class="pre">%scope_id</span></code> part anymore. In order to get full IPv6 address use

  2022. <a class="reference internal" href="#socket.getnameinfo" title="socket.getnameinfo"><code class="xref py py-func docutils literal notranslate"><span class="pre">getnameinfo()</span></code></a>.</p>

  2023. </div>

  2024. </dd></dl>

  2025. 

  2026. <dl class="py method">

  2027. <dt class="sig sig-object py" id="socket.socket.recvmsg">

  2028. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recvmsg</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bufsize</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">ancbufsize</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recvmsg" title="Link to this definition">¶</a></dt>

  2029. <dd><p>Receive normal data (up to <em>bufsize</em> bytes) and ancillary data from

  2030. the socket.  The <em>ancbufsize</em> argument sets the size in bytes of

  2031. the internal buffer used to receive the ancillary data; it defaults

  2032. to 0, meaning that no ancillary data will be received.  Appropriate

  2033. buffer sizes for ancillary data can be calculated using

  2034. <a class="reference internal" href="#socket.CMSG_SPACE" title="socket.CMSG_SPACE"><code class="xref py py-func docutils literal notranslate"><span class="pre">CMSG_SPACE()</span></code></a> or <a class="reference internal" href="#socket.CMSG_LEN" title="socket.CMSG_LEN"><code class="xref py py-func docutils literal notranslate"><span class="pre">CMSG_LEN()</span></code></a>, and items which do not fit

  2035. into the buffer might be truncated or discarded.  The <em>flags</em>

  2036. argument defaults to 0 and has the same meaning as for

  2037. <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a>.</p>

  2038. <p>The return value is a 4-tuple: <code class="docutils literal notranslate"><span class="pre">(data,</span> <span class="pre">ancdata,</span> <span class="pre">msg_flags,</span>

  2039. <span class="pre">address)</span></code>.  The <em>data</em> item is a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object holding the

  2040. non-ancillary data received.  The <em>ancdata</em> item is a list of zero

  2041. or more tuples <code class="docutils literal notranslate"><span class="pre">(cmsg_level,</span> <span class="pre">cmsg_type,</span> <span class="pre">cmsg_data)</span></code> representing

  2042. the ancillary data (control messages) received: <em>cmsg_level</em> and

  2043. <em>cmsg_type</em> are integers specifying the protocol level and

  2044. protocol-specific type respectively, and <em>cmsg_data</em> is a

  2045. <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object holding the associated data.  The <em>msg_flags</em>

  2046. item is the bitwise OR of various flags indicating conditions on

  2047. the received message; see your system documentation for details.

  2048. If the receiving socket is unconnected, <em>address</em> is the address of

  2049. the sending socket, if available; otherwise, its value is

  2050. unspecified.</p>

  2051. <p>On some systems, <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a> and <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> can be used to

  2052. pass file descriptors between processes over an <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a>

  2053. socket.  When this facility is used (it is often restricted to

  2054. <a class="reference internal" href="#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code></a> sockets), <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> will return, in its

  2055. ancillary data, items of the form <code class="docutils literal notranslate"><span class="pre">(socket.SOL_SOCKET,</span>

  2056. <span class="pre">socket.SCM_RIGHTS,</span> <span class="pre">fds)</span></code>, where <em>fds</em> is a <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> object

  2057. representing the new file descriptors as a binary array of the

  2058. native C <span class="c-expr sig sig-inline c"><span class="kt">int</span></span> type.  If <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> raises an

  2059. exception after the system call returns, it will first attempt to

  2060. close any file descriptors received via this mechanism.</p>

  2061. <p>Some systems do not indicate the truncated length of ancillary data

  2062. items which have been only partially received.  If an item appears

  2063. to extend beyond the end of the buffer, <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> will issue

  2064. a <a class="reference internal" href="exceptions.html#RuntimeWarning" title="RuntimeWarning"><code class="xref py py-exc docutils literal notranslate"><span class="pre">RuntimeWarning</span></code></a>, and will return the part of it which is

  2065. inside the buffer provided it has not been truncated before the

  2066. start of its associated data.</p>

  2067. <p>On systems which support the <code class="xref py py-const docutils literal notranslate"><span class="pre">SCM_RIGHTS</span></code> mechanism, the

  2068. following function will receive up to <em>maxfds</em> file descriptors,

  2069. returning the message data and a list containing the descriptors

  2070. (while ignoring unexpected conditions such as unrelated control

  2071. messages being received).  See also <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a>.</p>

  2072. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">socket</span><span class="o">,</span> <span class="nn">array</span>

  2073. 

  2074. <span class="k">def</span> <span class="nf">recv_fds</span><span class="p">(</span><span class="n">sock</span><span class="p">,</span> <span class="n">msglen</span><span class="p">,</span> <span class="n">maxfds</span><span class="p">):</span>

  2075.     <span class="n">fds</span> <span class="o">=</span> <span class="n">array</span><span class="o">.</span><span class="n">array</span><span class="p">(</span><span class="s2">&quot;i&quot;</span><span class="p">)</span>   <span class="c1"># Array of ints</span>

  2076.     <span class="n">msg</span><span class="p">,</span> <span class="n">ancdata</span><span class="p">,</span> <span class="n">flags</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">sock</span><span class="o">.</span><span class="n">recvmsg</span><span class="p">(</span><span class="n">msglen</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">CMSG_LEN</span><span class="p">(</span><span class="n">maxfds</span> <span class="o">*</span> <span class="n">fds</span><span class="o">.</span><span class="n">itemsize</span><span class="p">))</span>

  2077.     <span class="k">for</span> <span class="n">cmsg_level</span><span class="p">,</span> <span class="n">cmsg_type</span><span class="p">,</span> <span class="n">cmsg_data</span> <span class="ow">in</span> <span class="n">ancdata</span><span class="p">:</span>

  2078.         <span class="k">if</span> <span class="n">cmsg_level</span> <span class="o">==</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOL_SOCKET</span> <span class="ow">and</span> <span class="n">cmsg_type</span> <span class="o">==</span> <span class="n">socket</span><span class="o">.</span><span class="n">SCM_RIGHTS</span><span class="p">:</span>

  2079.             <span class="c1"># Append data, ignoring any truncated integers at the end.</span>

  2080.             <span class="n">fds</span><span class="o">.</span><span class="n">frombytes</span><span class="p">(</span><span class="n">cmsg_data</span><span class="p">[:</span><span class="nb">len</span><span class="p">(</span><span class="n">cmsg_data</span><span class="p">)</span> <span class="o">-</span> <span class="p">(</span><span class="nb">len</span><span class="p">(</span><span class="n">cmsg_data</span><span class="p">)</span> <span class="o">%</span> <span class="n">fds</span><span class="o">.</span><span class="n">itemsize</span><span class="p">)])</span>

  2081.     <span class="k">return</span> <span class="n">msg</span><span class="p">,</span> <span class="nb">list</span><span class="p">(</span><span class="n">fds</span><span class="p">)</span>

  2082. </pre></div>

  2083. </div>

  2084. <div class="availability docutils container">

  2085. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix.</p>

  2086. <p>Most Unix platforms.</p>

  2087. </div>

  2088. <div class="versionadded">

  2089. <p><span class="versionmodified added">New in version 3.3.</span></p>

  2090. </div>

  2091. <div class="versionchanged">

  2092. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2093. an exception, the method now retries the system call instead of raising

  2094. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-9"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2095. </div>

  2096. </dd></dl>

  2097. 

  2098. <dl class="py method">

  2099. <dt class="sig sig-object py" id="socket.socket.recvmsg_into">

  2100. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recvmsg_into</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">buffers</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">ancbufsize</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recvmsg_into" title="Link to this definition">¶</a></dt>

  2101. <dd><p>Receive normal data and ancillary data from the socket, behaving as

  2102. <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a> would, but scatter the non-ancillary data into a

  2103. series of buffers instead of returning a new bytes object.  The

  2104. <em>buffers</em> argument must be an iterable of objects that export

  2105. writable buffers (e.g. <a class="reference internal" href="stdtypes.html#bytearray" title="bytearray"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytearray</span></code></a> objects); these will be

  2106. filled with successive chunks of the non-ancillary data until it

  2107. has all been written or there are no more buffers.  The operating

  2108. system may set a limit (<a class="reference internal" href="os.html#os.sysconf" title="os.sysconf"><code class="xref py py-func docutils literal notranslate"><span class="pre">sysconf()</span></code></a> value <code class="docutils literal notranslate"><span class="pre">SC_IOV_MAX</span></code>)

  2109. on the number of buffers that can be used.  The <em>ancbufsize</em> and

  2110. <em>flags</em> arguments have the same meaning as for <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a>.</p>

  2111. <p>The return value is a 4-tuple: <code class="docutils literal notranslate"><span class="pre">(nbytes,</span> <span class="pre">ancdata,</span> <span class="pre">msg_flags,</span>

  2112. <span class="pre">address)</span></code>, where <em>nbytes</em> is the total number of bytes of

  2113. non-ancillary data written into the buffers, and <em>ancdata</em>,

  2114. <em>msg_flags</em> and <em>address</em> are the same as for <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a>.</p>

  2115. <p>Example:</p>

  2116. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="gp">&gt;&gt;&gt; </span><span class="kn">import</span> <span class="nn">socket</span>

  2117. <span class="gp">&gt;&gt;&gt; </span><span class="n">s1</span><span class="p">,</span> <span class="n">s2</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socketpair</span><span class="p">()</span>

  2118. <span class="gp">&gt;&gt;&gt; </span><span class="n">b1</span> <span class="o">=</span> <span class="nb">bytearray</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;----&#39;</span><span class="p">)</span>

  2119. <span class="gp">&gt;&gt;&gt; </span><span class="n">b2</span> <span class="o">=</span> <span class="nb">bytearray</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;0123456789&#39;</span><span class="p">)</span>

  2120. <span class="gp">&gt;&gt;&gt; </span><span class="n">b3</span> <span class="o">=</span> <span class="nb">bytearray</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;--------------&#39;</span><span class="p">)</span>

  2121. <span class="gp">&gt;&gt;&gt; </span><span class="n">s1</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;Mary had a little lamb&#39;</span><span class="p">)</span>

  2122. <span class="go">22</span>

  2123. <span class="gp">&gt;&gt;&gt; </span><span class="n">s2</span><span class="o">.</span><span class="n">recvmsg_into</span><span class="p">([</span><span class="n">b1</span><span class="p">,</span> <span class="nb">memoryview</span><span class="p">(</span><span class="n">b2</span><span class="p">)[</span><span class="mi">2</span><span class="p">:</span><span class="mi">9</span><span class="p">],</span> <span class="n">b3</span><span class="p">])</span>

  2124. <span class="go">(22, [], 0, None)</span>

  2125. <span class="gp">&gt;&gt;&gt; </span><span class="p">[</span><span class="n">b1</span><span class="p">,</span> <span class="n">b2</span><span class="p">,</span> <span class="n">b3</span><span class="p">]</span>

  2126. <span class="go">[bytearray(b&#39;Mary&#39;), bytearray(b&#39;01 had a 9&#39;), bytearray(b&#39;little lamb---&#39;)]</span>

  2127. </pre></div>

  2128. </div>

  2129. <div class="availability docutils container">

  2130. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix.</p>

  2131. <p>Most Unix platforms.</p>

  2132. </div>

  2133. <div class="versionadded">

  2134. <p><span class="versionmodified added">New in version 3.3.</span></p>

  2135. </div>

  2136. </dd></dl>

  2137. 

  2138. <dl class="py method">

  2139. <dt class="sig sig-object py" id="socket.socket.recvfrom_into">

  2140. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recvfrom_into</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">buffer</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">nbytes</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recvfrom_into" title="Link to this definition">¶</a></dt>

  2141. <dd><p>Receive data from the socket, writing it into <em>buffer</em> instead of creating a

  2142. new bytestring.  The return value is a pair <code class="docutils literal notranslate"><span class="pre">(nbytes,</span> <span class="pre">address)</span></code> where <em>nbytes</em> is

  2143. the number of bytes received and <em>address</em> is the address of the socket sending

  2144. the data.  See the Unix manual page <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/recv(2)">recv(2)</a></em> for the meaning of the

  2145. optional argument <em>flags</em>; it defaults to zero.  (The format of <em>address</em>

  2146. depends on the address family — see above.)</p>

  2147. </dd></dl>

  2148. 

  2149. <dl class="py method">

  2150. <dt class="sig sig-object py" id="socket.socket.recv_into">

  2151. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">recv_into</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">buffer</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">nbytes</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.recv_into" title="Link to this definition">¶</a></dt>

  2152. <dd><p>Receive up to <em>nbytes</em> bytes from the socket, storing the data into a buffer

  2153. rather than creating a new bytestring.  If <em>nbytes</em> is not specified (or 0),

  2154. receive up to the size available in the given buffer.  Returns the number of

  2155. bytes received.  See the Unix manual page <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/recv(2)">recv(2)</a></em> for the meaning

  2156. of the optional argument <em>flags</em>; it defaults to zero.</p>

  2157. </dd></dl>

  2158. 

  2159. <dl class="py method">

  2160. <dt class="sig sig-object py" id="socket.socket.send">

  2161. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">send</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bytes</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.send" title="Link to this definition">¶</a></dt>

  2162. <dd><p>Send data to the socket.  The socket must be connected to a remote socket.  The

  2163. optional <em>flags</em> argument has the same meaning as for <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a> above.

  2164. Returns the number of bytes sent. Applications are responsible for checking that

  2165. all data has been sent; if only some of the data was transmitted, the

  2166. application needs to attempt delivery of the remaining data. For further

  2167. information on this topic, consult the <a class="reference internal" href="../howto/sockets.html#socket-howto"><span class="std std-ref">Socket Programming HOWTO</span></a>.</p>

  2168. <div class="versionchanged">

  2169. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2170. an exception, the method now retries the system call instead of raising

  2171. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-10"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2172. </div>

  2173. </dd></dl>

  2174. 

  2175. <dl class="py method">

  2176. <dt class="sig sig-object py" id="socket.socket.sendall">

  2177. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendall</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bytes</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.sendall" title="Link to this definition">¶</a></dt>

  2178. <dd><p>Send data to the socket.  The socket must be connected to a remote socket.  The

  2179. optional <em>flags</em> argument has the same meaning as for <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a> above.

  2180. Unlike <a class="reference internal" href="#socket.socket.send" title="socket.socket.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a>, this method continues to send data from <em>bytes</em> until

  2181. either all data has been sent or an error occurs.  <code class="docutils literal notranslate"><span class="pre">None</span></code> is returned on

  2182. success.  On error, an exception is raised, and there is no way to determine how

  2183. much data, if any, was successfully sent.</p>

  2184. <div class="versionchanged">

  2185. <p><span class="versionmodified changed">Changed in version 3.5: </span>The socket timeout is no longer reset each time data is sent successfully.

  2186. The socket timeout is now the maximum total duration to send all data.</p>

  2187. </div>

  2188. <div class="versionchanged">

  2189. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2190. an exception, the method now retries the system call instead of raising

  2191. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-11"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2192. </div>

  2193. </dd></dl>

  2194. 

  2195. <dl class="py method">

  2196. <dt class="sig sig-object py" id="socket.socket.sendto">

  2197. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendto</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bytes</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.sendto" title="Link to this definition">¶</a></dt>

  2198. <dt class="sig sig-object py">

  2199. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendto</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">bytes</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="sig-paren">)</span></dt>

  2200. <dd><p>Send data to the socket.  The socket should not be connected to a remote socket,

  2201. since the destination socket is specified by <em>address</em>.  The optional <em>flags</em>

  2202. argument has the same meaning as for <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a> above.  Return the number of

  2203. bytes sent. (The format of <em>address</em> depends on the address family — see

  2204. above.)</p>

  2205. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.sendto</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">address</span></code>.</p>

  2206. <div class="versionchanged">

  2207. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2208. an exception, the method now retries the system call instead of raising

  2209. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-12"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2210. </div>

  2211. </dd></dl>

  2212. 

  2213. <dl class="py method">

  2214. <dt class="sig sig-object py" id="socket.socket.sendmsg">

  2215. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendmsg</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">buffers</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">ancdata</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">address</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.sendmsg" title="Link to this definition">¶</a></dt>

  2216. <dd><p>Send normal and ancillary data to the socket, gathering the

  2217. non-ancillary data from a series of buffers and concatenating it

  2218. into a single message.  The <em>buffers</em> argument specifies the

  2219. non-ancillary data as an iterable of

  2220. <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like objects</span></a>

  2221. (e.g. <a class="reference internal" href="stdtypes.html#bytes" title="bytes"><code class="xref py py-class docutils literal notranslate"><span class="pre">bytes</span></code></a> objects); the operating system may set a limit

  2222. (<a class="reference internal" href="os.html#os.sysconf" title="os.sysconf"><code class="xref py py-func docutils literal notranslate"><span class="pre">sysconf()</span></code></a> value <code class="docutils literal notranslate"><span class="pre">SC_IOV_MAX</span></code>) on the number of buffers

  2223. that can be used.  The <em>ancdata</em> argument specifies the ancillary

  2224. data (control messages) as an iterable of zero or more tuples

  2225. <code class="docutils literal notranslate"><span class="pre">(cmsg_level,</span> <span class="pre">cmsg_type,</span> <span class="pre">cmsg_data)</span></code>, where <em>cmsg_level</em> and

  2226. <em>cmsg_type</em> are integers specifying the protocol level and

  2227. protocol-specific type respectively, and <em>cmsg_data</em> is a

  2228. bytes-like object holding the associated data.  Note that

  2229. some systems (in particular, systems without <a class="reference internal" href="#socket.CMSG_SPACE" title="socket.CMSG_SPACE"><code class="xref py py-func docutils literal notranslate"><span class="pre">CMSG_SPACE()</span></code></a>)

  2230. might support sending only one control message per call.  The

  2231. <em>flags</em> argument defaults to 0 and has the same meaning as for

  2232. <a class="reference internal" href="#socket.socket.send" title="socket.socket.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a>.  If <em>address</em> is supplied and not <code class="docutils literal notranslate"><span class="pre">None</span></code>, it sets a

  2233. destination address for the message.  The return value is the

  2234. number of bytes of non-ancillary data sent.</p>

  2235. <p>The following function sends the list of file descriptors <em>fds</em>

  2236. over an <a class="reference internal" href="#socket.AF_UNIX" title="socket.AF_UNIX"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_UNIX</span></code></a> socket, on systems which support the

  2237. <code class="xref py py-const docutils literal notranslate"><span class="pre">SCM_RIGHTS</span></code> mechanism.  See also <a class="reference internal" href="#socket.socket.recvmsg" title="socket.socket.recvmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recvmsg()</span></code></a>.</p>

  2238. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">socket</span><span class="o">,</span> <span class="nn">array</span>

  2239. 

  2240. <span class="k">def</span> <span class="nf">send_fds</span><span class="p">(</span><span class="n">sock</span><span class="p">,</span> <span class="n">msg</span><span class="p">,</span> <span class="n">fds</span><span class="p">):</span>

  2241.     <span class="k">return</span> <span class="n">sock</span><span class="o">.</span><span class="n">sendmsg</span><span class="p">([</span><span class="n">msg</span><span class="p">],</span> <span class="p">[(</span><span class="n">socket</span><span class="o">.</span><span class="n">SOL_SOCKET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SCM_RIGHTS</span><span class="p">,</span> <span class="n">array</span><span class="o">.</span><span class="n">array</span><span class="p">(</span><span class="s2">&quot;i&quot;</span><span class="p">,</span> <span class="n">fds</span><span class="p">))])</span>

  2242. </pre></div>

  2243. </div>

  2244. <div class="availability docutils container">

  2245. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Unix, not WASI.</p>

  2246. <p>Most Unix platforms.</p>

  2247. </div>

  2248. <p class="audit-hook">Raises an <a class="reference internal" href="sys.html#auditing"><span class="std std-ref">auditing event</span></a> <code class="docutils literal notranslate"><span class="pre">socket.sendmsg</span></code> with arguments <code class="docutils literal notranslate"><span class="pre">self</span></code>, <code class="docutils literal notranslate"><span class="pre">address</span></code>.</p>

  2249. <div class="versionadded">

  2250. <p><span class="versionmodified added">New in version 3.3.</span></p>

  2251. </div>

  2252. <div class="versionchanged">

  2253. <p><span class="versionmodified changed">Changed in version 3.5: </span>If the system call is interrupted and the signal handler does not raise

  2254. an exception, the method now retries the system call instead of raising

  2255. an <a class="reference internal" href="exceptions.html#InterruptedError" title="InterruptedError"><code class="xref py py-exc docutils literal notranslate"><span class="pre">InterruptedError</span></code></a> exception (see <span class="target" id="index-13"></span><a class="pep reference external" href="https://peps.python.org/pep-0475/"><strong>PEP 475</strong></a> for the rationale).</p>

  2256. </div>

  2257. </dd></dl>

  2258. 

  2259. <dl class="py method">

  2260. <dt class="sig sig-object py" id="socket.socket.sendmsg_afalg">

  2261. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendmsg_afalg</span></span><span class="sig-paren">(</span><span class="optional">[</span><em class="sig-param"><span class="n"><span class="pre">msg</span></span></em>, <span class="optional">]</span><em class="sig-param"><span class="n"><span class="pre">*</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">op</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">iv</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">assoclen</span></span></em><span class="optional">[</span>, <em class="sig-param"><span class="n"><span class="pre">flags</span></span></em><span class="optional">]</span><span class="optional">]</span><span class="optional">]</span><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.sendmsg_afalg" title="Link to this definition">¶</a></dt>

  2262. <dd><p>Specialized version of <a class="reference internal" href="#socket.socket.sendmsg" title="socket.socket.sendmsg"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendmsg()</span></code></a> for <a class="reference internal" href="#socket.AF_ALG" title="socket.AF_ALG"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_ALG</span></code></a> socket.

  2263. Set mode, IV, AEAD associated data length and flags for <a class="reference internal" href="#socket.AF_ALG" title="socket.AF_ALG"><code class="xref py py-const docutils literal notranslate"><span class="pre">AF_ALG</span></code></a> socket.</p>

  2264. <div class="availability docutils container">

  2265. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Linux &gt;= 2.6.38.</p>

  2266. </div>

  2267. <div class="versionadded">

  2268. <p><span class="versionmodified added">New in version 3.6.</span></p>

  2269. </div>

  2270. </dd></dl>

  2271. 

  2272. <dl class="py method">

  2273. <dt class="sig sig-object py" id="socket.socket.sendfile">

  2274. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">sendfile</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">file</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">offset</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">0</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">count</span></span><span class="o"><span class="pre">=</span></span><span class="default_value"><span class="pre">None</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.sendfile" title="Link to this definition">¶</a></dt>

  2275. <dd><p>Send a file until EOF is reached by using high-performance

  2276. <a class="reference internal" href="os.html#os.sendfile" title="os.sendfile"><code class="xref py py-mod docutils literal notranslate"><span class="pre">os.sendfile</span></code></a> and return the total number of bytes which were sent.

  2277. <em>file</em> must be a regular file object opened in binary mode. If

  2278. <a class="reference internal" href="os.html#os.sendfile" title="os.sendfile"><code class="xref py py-mod docutils literal notranslate"><span class="pre">os.sendfile</span></code></a> is not available (e.g. Windows) or <em>file</em> is not a

  2279. regular file <a class="reference internal" href="#socket.socket.send" title="socket.socket.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a> will be used instead. <em>offset</em> tells from where to

  2280. start reading the file. If specified, <em>count</em> is the total number of bytes

  2281. to transmit as opposed to sending the file until EOF is reached. File

  2282. position is updated on return or also in case of error in which case

  2283. <a class="reference internal" href="io.html#io.IOBase.tell" title="io.IOBase.tell"><code class="xref py py-meth docutils literal notranslate"><span class="pre">file.tell()</span></code></a> can be used to figure out the number of

  2284. bytes which were sent. The socket must be of <a class="reference internal" href="#socket.SOCK_STREAM" title="socket.SOCK_STREAM"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_STREAM</span></code></a> type.

  2285. Non-blocking sockets are not supported.</p>

  2286. <div class="versionadded">

  2287. <p><span class="versionmodified added">New in version 3.5.</span></p>

  2288. </div>

  2289. </dd></dl>

  2290. 

  2291. <dl class="py method">

  2292. <dt class="sig sig-object py" id="socket.socket.set_inheritable">

  2293. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">set_inheritable</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">inheritable</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.set_inheritable" title="Link to this definition">¶</a></dt>

  2294. <dd><p>Set the <a class="reference internal" href="os.html#fd-inheritance"><span class="std std-ref">inheritable flag</span></a> of the socket’s file

  2295. descriptor or socket’s handle.</p>

  2296. <div class="versionadded">

  2297. <p><span class="versionmodified added">New in version 3.4.</span></p>

  2298. </div>

  2299. </dd></dl>

  2300. 

  2301. <dl class="py method">

  2302. <dt class="sig sig-object py" id="socket.socket.setblocking">

  2303. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">setblocking</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">flag</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.setblocking" title="Link to this definition">¶</a></dt>

  2304. <dd><p>Set blocking or non-blocking mode of the socket: if <em>flag</em> is false, the

  2305. socket is set to non-blocking, else to blocking mode.</p>

  2306. <p>This method is a shorthand for certain <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a> calls:</p>

  2307. <ul class="simple">

  2308. <li><p><code class="docutils literal notranslate"><span class="pre">sock.setblocking(True)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">sock.settimeout(None)</span></code></p></li>

  2309. <li><p><code class="docutils literal notranslate"><span class="pre">sock.setblocking(False)</span></code> is equivalent to <code class="docutils literal notranslate"><span class="pre">sock.settimeout(0.0)</span></code></p></li>

  2310. </ul>

  2311. <div class="versionchanged">

  2312. <p><span class="versionmodified changed">Changed in version 3.7: </span>The method no longer applies <a class="reference internal" href="#socket.SOCK_NONBLOCK" title="socket.SOCK_NONBLOCK"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_NONBLOCK</span></code></a> flag on

  2313. <a class="reference internal" href="#socket.socket.type" title="socket.socket.type"><code class="xref py py-attr docutils literal notranslate"><span class="pre">socket.type</span></code></a>.</p>

  2314. </div>

  2315. </dd></dl>

  2316. 

  2317. <dl class="py method">

  2318. <dt class="sig sig-object py" id="socket.socket.settimeout">

  2319. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">settimeout</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">value</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.settimeout" title="Link to this definition">¶</a></dt>

  2320. <dd><p>Set a timeout on blocking socket operations.  The <em>value</em> argument can be a

  2321. nonnegative floating point number expressing seconds, or <code class="docutils literal notranslate"><span class="pre">None</span></code>.

  2322. If a non-zero value is given, subsequent socket operations will raise a

  2323. <a class="reference internal" href="#socket.timeout" title="socket.timeout"><code class="xref py py-exc docutils literal notranslate"><span class="pre">timeout</span></code></a> exception if the timeout period <em>value</em> has elapsed before

  2324. the operation has completed.  If zero is given, the socket is put in

  2325. non-blocking mode. If <code class="docutils literal notranslate"><span class="pre">None</span></code> is given, the socket is put in blocking mode.</p>

  2326. <p>For further information, please consult the <a class="reference internal" href="#socket-timeouts"><span class="std std-ref">notes on socket timeouts</span></a>.</p>

  2327. <div class="versionchanged">

  2328. <p><span class="versionmodified changed">Changed in version 3.7: </span>The method no longer toggles <a class="reference internal" href="#socket.SOCK_NONBLOCK" title="socket.SOCK_NONBLOCK"><code class="xref py py-const docutils literal notranslate"><span class="pre">SOCK_NONBLOCK</span></code></a> flag on

  2329. <a class="reference internal" href="#socket.socket.type" title="socket.socket.type"><code class="xref py py-attr docutils literal notranslate"><span class="pre">socket.type</span></code></a>.</p>

  2330. </div>

  2331. </dd></dl>

  2332. 

  2333. <dl class="py method">

  2334. <dt class="sig sig-object py" id="socket.socket.setsockopt">

  2335. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">setsockopt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">optname</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">value</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><a class="reference internal" href="functions.html#int" title="int"><span class="pre">int</span></a></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.setsockopt" title="Link to this definition">¶</a></dt>

  2336. <dd></dd></dl>

  2337. 

  2338. <dl class="py method">

  2339. <dt class="sig sig-object py">

  2340. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">setsockopt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">optname</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">value</span></span><span class="p"><span class="pre">:</span></span><span class="w"> </span><span class="n"><span class="pre">buffer</span></span></em><span class="sig-paren">)</span></dt>

  2341. <dd></dd></dl>

  2342. 

  2343. <dl class="py method">

  2344. <dt class="sig sig-object py">

  2345. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">setsockopt</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">level</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">optname</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">None</span></span></em>, <em class="sig-param"><span class="n"><span class="pre">optlen:</span> <span class="pre">int</span></span></em><span class="sig-paren">)</span></dt>

  2346. <dd><p id="index-14">Set the value of the given socket option (see the Unix manual page

  2347. <em class="manpage"><a class="manpage reference external" href="https://manpages.debian.org/setsockopt(2)">setsockopt(2)</a></em>).  The needed symbolic constants are defined in this

  2348. module (<span class="xref std std-ref">SO_* etc. &lt;socket-unix-constants&gt;</span>).  The value can be an integer,

  2349. <code class="docutils literal notranslate"><span class="pre">None</span></code> or a <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> representing a buffer. In the later

  2350. case it is up to the caller to ensure that the bytestring contains the

  2351. proper bits (see the optional built-in module <a class="reference internal" href="struct.html#module-struct" title="struct: Interpret bytes as packed binary data."><code class="xref py py-mod docutils literal notranslate"><span class="pre">struct</span></code></a> for a way to

  2352. encode C structures as bytestrings). When <em>value</em> is set to <code class="docutils literal notranslate"><span class="pre">None</span></code>,

  2353. <em>optlen</em> argument is required. It’s equivalent to call <code class="xref c c-func docutils literal notranslate"><span class="pre">setsockopt()</span></code> C

  2354. function with <code class="docutils literal notranslate"><span class="pre">optval=NULL</span></code> and <code class="docutils literal notranslate"><span class="pre">optlen=optlen</span></code>.</p>

  2355. <div class="versionchanged">

  2356. <p><span class="versionmodified changed">Changed in version 3.5: </span>Writable <a class="reference internal" href="../glossary.html#term-bytes-like-object"><span class="xref std std-term">bytes-like object</span></a> is now accepted.</p>

  2357. </div>

  2358. <div class="versionchanged">

  2359. <p><span class="versionmodified changed">Changed in version 3.6: </span>setsockopt(level, optname, None, optlen: int) form added.</p>

  2360. </div>

  2361. <div class="availability docutils container">

  2362. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  2363. </div>

  2364. </dd></dl>

  2365. 

  2366. <dl class="py method">

  2367. <dt class="sig sig-object py" id="socket.socket.shutdown">

  2368. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">shutdown</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">how</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.shutdown" title="Link to this definition">¶</a></dt>

  2369. <dd><p>Shut down one or both halves of the connection.  If <em>how</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">SHUT_RD</span></code>,

  2370. further receives are disallowed.  If <em>how</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">SHUT_WR</span></code>, further sends

  2371. are disallowed.  If <em>how</em> is <code class="xref py py-const docutils literal notranslate"><span class="pre">SHUT_RDWR</span></code>, further sends and receives are

  2372. disallowed.</p>

  2373. <div class="availability docutils container">

  2374. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: not WASI.</p>

  2375. </div>

  2376. </dd></dl>

  2377. 

  2378. <dl class="py method">

  2379. <dt class="sig sig-object py" id="socket.socket.share">

  2380. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">share</span></span><span class="sig-paren">(</span><em class="sig-param"><span class="n"><span class="pre">process_id</span></span></em><span class="sig-paren">)</span><a class="headerlink" href="#socket.socket.share" title="Link to this definition">¶</a></dt>

  2381. <dd><p>Duplicate a socket and prepare it for sharing with a target process.  The

  2382. target process must be provided with <em>process_id</em>.  The resulting bytes object

  2383. can then be passed to the target process using some form of interprocess

  2384. communication and the socket can be recreated there using <a class="reference internal" href="#socket.fromshare" title="socket.fromshare"><code class="xref py py-func docutils literal notranslate"><span class="pre">fromshare()</span></code></a>.

  2385. Once this method has been called, it is safe to close the socket since

  2386. the operating system has already duplicated it for the target process.</p>

  2387. <div class="availability docutils container">

  2388. <p><a class="reference internal" href="intro.html#availability"><span class="std std-ref">Availability</span></a>: Windows.</p>

  2389. </div>

  2390. <div class="versionadded">

  2391. <p><span class="versionmodified added">New in version 3.3.</span></p>

  2392. </div>

  2393. </dd></dl>

  2394. 

  2395. <p>Note that there are no methods <code class="xref py py-meth docutils literal notranslate"><span class="pre">read()</span></code> or <code class="xref py py-meth docutils literal notranslate"><span class="pre">write()</span></code>; use

  2396. <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a> and <a class="reference internal" href="#socket.socket.send" title="socket.socket.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">send()</span></code></a> without <em>flags</em> argument instead.</p>

  2397. <p>Socket objects also have these (read-only) attributes that correspond to the

  2398. values given to the <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-class docutils literal notranslate"><span class="pre">socket</span></code></a> constructor.</p>

  2399. <dl class="py attribute">

  2400. <dt class="sig sig-object py" id="socket.socket.family">

  2401. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">family</span></span><a class="headerlink" href="#socket.socket.family" title="Link to this definition">¶</a></dt>

  2402. <dd><p>The socket family.</p>

  2403. </dd></dl>

  2404. 

  2405. <dl class="py attribute">

  2406. <dt class="sig sig-object py" id="socket.socket.type">

  2407. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">type</span></span><a class="headerlink" href="#socket.socket.type" title="Link to this definition">¶</a></dt>

  2408. <dd><p>The socket type.</p>

  2409. </dd></dl>

  2410. 

  2411. <dl class="py attribute">

  2412. <dt class="sig sig-object py" id="socket.socket.proto">

  2413. <span class="sig-prename descclassname"><span class="pre">socket.</span></span><span class="sig-name descname"><span class="pre">proto</span></span><a class="headerlink" href="#socket.socket.proto" title="Link to this definition">¶</a></dt>

  2414. <dd><p>The socket protocol.</p>

  2415. </dd></dl>

  2416. 

  2417. </section>

  2418. <section id="notes-on-socket-timeouts">

  2419. <span id="socket-timeouts"></span><h2>Notes on socket timeouts<a class="headerlink" href="#notes-on-socket-timeouts" title="Link to this heading">¶</a></h2>

  2420. <p>A socket object can be in one of three modes: blocking, non-blocking, or

  2421. timeout.  Sockets are by default always created in blocking mode, but this

  2422. can be changed by calling <a class="reference internal" href="#socket.setdefaulttimeout" title="socket.setdefaulttimeout"><code class="xref py py-func docutils literal notranslate"><span class="pre">setdefaulttimeout()</span></code></a>.</p>

  2423. <ul class="simple">

  2424. <li><p>In <em>blocking mode</em>, operations block until complete or the system returns

  2425. an error (such as connection timed out).</p></li>

  2426. <li><p>In <em>non-blocking mode</em>, operations fail (with an error that is unfortunately

  2427. system-dependent) if they cannot be completed immediately: functions from the

  2428. <a class="reference internal" href="select.html#module-select" title="select: Wait for I/O completion on multiple streams."><code class="xref py py-mod docutils literal notranslate"><span class="pre">select</span></code></a> module can be used to know when and whether a socket is available

  2429. for reading or writing.</p></li>

  2430. <li><p>In <em>timeout mode</em>, operations fail if they cannot be completed within the

  2431. timeout specified for the socket (they raise a <a class="reference internal" href="#socket.timeout" title="socket.timeout"><code class="xref py py-exc docutils literal notranslate"><span class="pre">timeout</span></code></a> exception)

  2432. or if the system returns an error.</p></li>

  2433. </ul>

  2434. <div class="admonition note">

  2435. <p class="admonition-title">Note</p>

  2436. <p>At the operating system level, sockets in <em>timeout mode</em> are internally set

  2437. in non-blocking mode.  Also, the blocking and timeout modes are shared between

  2438. file descriptors and socket objects that refer to the same network endpoint.

  2439. This implementation detail can have visible consequences if e.g. you decide

  2440. to use the <a class="reference internal" href="#socket.socket.fileno" title="socket.socket.fileno"><code class="xref py py-meth docutils literal notranslate"><span class="pre">fileno()</span></code></a> of a socket.</p>

  2441. </div>

  2442. <section id="timeouts-and-the-connect-method">

  2443. <h3>Timeouts and the <code class="docutils literal notranslate"><span class="pre">connect</span></code> method<a class="headerlink" href="#timeouts-and-the-connect-method" title="Link to this heading">¶</a></h3>

  2444. <p>The <a class="reference internal" href="#socket.socket.connect" title="socket.socket.connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connect()</span></code></a> operation is also subject to the timeout

  2445. setting, and in general it is recommended to call <a class="reference internal" href="#socket.socket.settimeout" title="socket.socket.settimeout"><code class="xref py py-meth docutils literal notranslate"><span class="pre">settimeout()</span></code></a>

  2446. before calling <a class="reference internal" href="#socket.socket.connect" title="socket.socket.connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connect()</span></code></a> or pass a timeout parameter to

  2447. <a class="reference internal" href="#socket.create_connection" title="socket.create_connection"><code class="xref py py-meth docutils literal notranslate"><span class="pre">create_connection()</span></code></a>.  However, the system network stack may also

  2448. return a connection timeout error of its own regardless of any Python socket

  2449. timeout setting.</p>

  2450. </section>

  2451. <section id="timeouts-and-the-accept-method">

  2452. <h3>Timeouts and the <code class="docutils literal notranslate"><span class="pre">accept</span></code> method<a class="headerlink" href="#timeouts-and-the-accept-method" title="Link to this heading">¶</a></h3>

  2453. <p>If <a class="reference internal" href="#socket.getdefaulttimeout" title="socket.getdefaulttimeout"><code class="xref py py-func docutils literal notranslate"><span class="pre">getdefaulttimeout()</span></code></a> is not <a class="reference internal" href="constants.html#None" title="None"><code class="xref py py-const docutils literal notranslate"><span class="pre">None</span></code></a>, sockets returned by

  2454. the <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a> method inherit that timeout.  Otherwise, the

  2455. behaviour depends on settings of the listening socket:</p>

  2456. <ul class="simple">

  2457. <li><p>if the listening socket is in <em>blocking mode</em> or in <em>timeout mode</em>,

  2458. the socket returned by <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a> is in <em>blocking mode</em>;</p></li>

  2459. <li><p>if the listening socket is in <em>non-blocking mode</em>, whether the socket

  2460. returned by <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a> is in blocking or non-blocking mode

  2461. is operating system-dependent.  If you want to ensure cross-platform

  2462. behaviour, it is recommended you manually override this setting.</p></li>

  2463. </ul>

  2464. </section>

  2465. </section>

  2466. <section id="example">

  2467. <span id="socket-example"></span><h2>Example<a class="headerlink" href="#example" title="Link to this heading">¶</a></h2>

  2468. <p>Here are four minimal example programs using the TCP/IP protocol: a server that

  2469. echoes all data that it receives back (servicing only one client), and a client

  2470. using it.  Note that a server must perform the sequence <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a>,

  2471. <a class="reference internal" href="#socket.socket.bind" title="socket.socket.bind"><code class="xref py py-meth docutils literal notranslate"><span class="pre">bind()</span></code></a>, <a class="reference internal" href="#socket.socket.listen" title="socket.socket.listen"><code class="xref py py-meth docutils literal notranslate"><span class="pre">listen()</span></code></a>, <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a> (possibly

  2472. repeating the <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a> to service more than one client), while a

  2473. client only needs the sequence <a class="reference internal" href="#socket.socket" title="socket.socket"><code class="xref py py-func docutils literal notranslate"><span class="pre">socket()</span></code></a>, <a class="reference internal" href="#socket.socket.connect" title="socket.socket.connect"><code class="xref py py-meth docutils literal notranslate"><span class="pre">connect()</span></code></a>.  Also

  2474. note that the server does not <a class="reference internal" href="#socket.socket.sendall" title="socket.socket.sendall"><code class="xref py py-meth docutils literal notranslate"><span class="pre">sendall()</span></code></a>/<a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">recv()</span></code></a> on

  2475. the socket it is listening on but on the new socket returned by

  2476. <a class="reference internal" href="#socket.socket.accept" title="socket.socket.accept"><code class="xref py py-meth docutils literal notranslate"><span class="pre">accept()</span></code></a>.</p>

  2477. <p>The first two examples support IPv4 only.</p>

  2478. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># Echo server program</span>

  2479. <span class="kn">import</span> <span class="nn">socket</span>

  2480. 

  2481. <span class="n">HOST</span> <span class="o">=</span> <span class="s1">&#39;&#39;</span>                 <span class="c1"># Symbolic name meaning all available interfaces</span>

  2482. <span class="n">PORT</span> <span class="o">=</span> <span class="mi">50007</span>              <span class="c1"># Arbitrary non-privileged port</span>

  2483. <span class="k">with</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_INET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span><span class="p">)</span> <span class="k">as</span> <span class="n">s</span><span class="p">:</span>

  2484.     <span class="n">s</span><span class="o">.</span><span class="n">bind</span><span class="p">((</span><span class="n">HOST</span><span class="p">,</span> <span class="n">PORT</span><span class="p">))</span>

  2485.     <span class="n">s</span><span class="o">.</span><span class="n">listen</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>

  2486.     <span class="n">conn</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span>

  2487.     <span class="k">with</span> <span class="n">conn</span><span class="p">:</span>

  2488.         <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Connected by&#39;</span><span class="p">,</span> <span class="n">addr</span><span class="p">)</span>

  2489.         <span class="k">while</span> <span class="kc">True</span><span class="p">:</span>

  2490.             <span class="n">data</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1024</span><span class="p">)</span>

  2491.             <span class="k">if</span> <span class="ow">not</span> <span class="n">data</span><span class="p">:</span> <span class="k">break</span>

  2492.             <span class="n">conn</span><span class="o">.</span><span class="n">sendall</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>

  2493. </pre></div>

  2494. </div>

  2495. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># Echo client program</span>

  2496. <span class="kn">import</span> <span class="nn">socket</span>

  2497. 

  2498. <span class="n">HOST</span> <span class="o">=</span> <span class="s1">&#39;daring.cwi.nl&#39;</span>    <span class="c1"># The remote host</span>

  2499. <span class="n">PORT</span> <span class="o">=</span> <span class="mi">50007</span>              <span class="c1"># The same port as used by the server</span>

  2500. <span class="k">with</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_INET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span><span class="p">)</span> <span class="k">as</span> <span class="n">s</span><span class="p">:</span>

  2501.     <span class="n">s</span><span class="o">.</span><span class="n">connect</span><span class="p">((</span><span class="n">HOST</span><span class="p">,</span> <span class="n">PORT</span><span class="p">))</span>

  2502.     <span class="n">s</span><span class="o">.</span><span class="n">sendall</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;Hello, world&#39;</span><span class="p">)</span>

  2503.     <span class="n">data</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1024</span><span class="p">)</span>

  2504. <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Received&#39;</span><span class="p">,</span> <span class="nb">repr</span><span class="p">(</span><span class="n">data</span><span class="p">))</span>

  2505. </pre></div>

  2506. </div>

  2507. <p>The next two examples are identical to the above two, but support both IPv4 and

  2508. IPv6. The server side will listen to the first address family available (it

  2509. should listen to both instead). On most of IPv6-ready systems, IPv6 will take

  2510. precedence and the server may not accept IPv4 traffic. The client side will try

  2511. to connect to all the addresses returned as a result of the name resolution, and

  2512. sends traffic to the first one connected successfully.</p>

  2513. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># Echo server program</span>

  2514. <span class="kn">import</span> <span class="nn">socket</span>

  2515. <span class="kn">import</span> <span class="nn">sys</span>

  2516. 

  2517. <span class="n">HOST</span> <span class="o">=</span> <span class="kc">None</span>               <span class="c1"># Symbolic name meaning all available interfaces</span>

  2518. <span class="n">PORT</span> <span class="o">=</span> <span class="mi">50007</span>              <span class="c1"># Arbitrary non-privileged port</span>

  2519. <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2520. <span class="k">for</span> <span class="n">res</span> <span class="ow">in</span> <span class="n">socket</span><span class="o">.</span><span class="n">getaddrinfo</span><span class="p">(</span><span class="n">HOST</span><span class="p">,</span> <span class="n">PORT</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">AF_UNSPEC</span><span class="p">,</span>

  2521.                               <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span><span class="p">,</span> <span class="mi">0</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">AI_PASSIVE</span><span class="p">):</span>

  2522.     <span class="n">af</span><span class="p">,</span> <span class="n">socktype</span><span class="p">,</span> <span class="n">proto</span><span class="p">,</span> <span class="n">canonname</span><span class="p">,</span> <span class="n">sa</span> <span class="o">=</span> <span class="n">res</span>

  2523.     <span class="k">try</span><span class="p">:</span>

  2524.         <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">af</span><span class="p">,</span> <span class="n">socktype</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>

  2525.     <span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">msg</span><span class="p">:</span>

  2526.         <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2527.         <span class="k">continue</span>

  2528.     <span class="k">try</span><span class="p">:</span>

  2529.         <span class="n">s</span><span class="o">.</span><span class="n">bind</span><span class="p">(</span><span class="n">sa</span><span class="p">)</span>

  2530.         <span class="n">s</span><span class="o">.</span><span class="n">listen</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>

  2531.     <span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">msg</span><span class="p">:</span>

  2532.         <span class="n">s</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>

  2533.         <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2534.         <span class="k">continue</span>

  2535.     <span class="k">break</span>

  2536. <span class="k">if</span> <span class="n">s</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>

  2537.     <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;could not open socket&#39;</span><span class="p">)</span>

  2538.     <span class="n">sys</span><span class="o">.</span><span class="n">exit</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>

  2539. <span class="n">conn</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">accept</span><span class="p">()</span>

  2540. <span class="k">with</span> <span class="n">conn</span><span class="p">:</span>

  2541.     <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Connected by&#39;</span><span class="p">,</span> <span class="n">addr</span><span class="p">)</span>

  2542.     <span class="k">while</span> <span class="kc">True</span><span class="p">:</span>

  2543.         <span class="n">data</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1024</span><span class="p">)</span>

  2544.         <span class="k">if</span> <span class="ow">not</span> <span class="n">data</span><span class="p">:</span> <span class="k">break</span>

  2545.         <span class="n">conn</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>

  2546. </pre></div>

  2547. </div>

  2548. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="c1"># Echo client program</span>

  2549. <span class="kn">import</span> <span class="nn">socket</span>

  2550. <span class="kn">import</span> <span class="nn">sys</span>

  2551. 

  2552. <span class="n">HOST</span> <span class="o">=</span> <span class="s1">&#39;daring.cwi.nl&#39;</span>    <span class="c1"># The remote host</span>

  2553. <span class="n">PORT</span> <span class="o">=</span> <span class="mi">50007</span>              <span class="c1"># The same port as used by the server</span>

  2554. <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2555. <span class="k">for</span> <span class="n">res</span> <span class="ow">in</span> <span class="n">socket</span><span class="o">.</span><span class="n">getaddrinfo</span><span class="p">(</span><span class="n">HOST</span><span class="p">,</span> <span class="n">PORT</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">AF_UNSPEC</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span><span class="p">):</span>

  2556.     <span class="n">af</span><span class="p">,</span> <span class="n">socktype</span><span class="p">,</span> <span class="n">proto</span><span class="p">,</span> <span class="n">canonname</span><span class="p">,</span> <span class="n">sa</span> <span class="o">=</span> <span class="n">res</span>

  2557.     <span class="k">try</span><span class="p">:</span>

  2558.         <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">af</span><span class="p">,</span> <span class="n">socktype</span><span class="p">,</span> <span class="n">proto</span><span class="p">)</span>

  2559.     <span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">msg</span><span class="p">:</span>

  2560.         <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2561.         <span class="k">continue</span>

  2562.     <span class="k">try</span><span class="p">:</span>

  2563.         <span class="n">s</span><span class="o">.</span><span class="n">connect</span><span class="p">(</span><span class="n">sa</span><span class="p">)</span>

  2564.     <span class="k">except</span> <span class="ne">OSError</span> <span class="k">as</span> <span class="n">msg</span><span class="p">:</span>

  2565.         <span class="n">s</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>

  2566.         <span class="n">s</span> <span class="o">=</span> <span class="kc">None</span>

  2567.         <span class="k">continue</span>

  2568.     <span class="k">break</span>

  2569. <span class="k">if</span> <span class="n">s</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>

  2570.     <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;could not open socket&#39;</span><span class="p">)</span>

  2571.     <span class="n">sys</span><span class="o">.</span><span class="n">exit</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>

  2572. <span class="k">with</span> <span class="n">s</span><span class="p">:</span>

  2573.     <span class="n">s</span><span class="o">.</span><span class="n">sendall</span><span class="p">(</span><span class="sa">b</span><span class="s1">&#39;Hello, world&#39;</span><span class="p">)</span>

  2574.     <span class="n">data</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">recv</span><span class="p">(</span><span class="mi">1024</span><span class="p">)</span>

  2575. <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Received&#39;</span><span class="p">,</span> <span class="nb">repr</span><span class="p">(</span><span class="n">data</span><span class="p">))</span>

  2576. </pre></div>

  2577. </div>

  2578. <p>The next example shows how to write a very simple network sniffer with raw

  2579. sockets on Windows. The example requires administrator privileges to modify

  2580. the interface:</p>

  2581. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">socket</span>

  2582. 

  2583. <span class="c1"># the public network interface</span>

  2584. <span class="n">HOST</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">gethostbyname</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">gethostname</span><span class="p">())</span>

  2585. 

  2586. <span class="c1"># create a raw socket and bind it to the public interface</span>

  2587. <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_INET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_RAW</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">IPPROTO_IP</span><span class="p">)</span>

  2588. <span class="n">s</span><span class="o">.</span><span class="n">bind</span><span class="p">((</span><span class="n">HOST</span><span class="p">,</span> <span class="mi">0</span><span class="p">))</span>

  2589. 

  2590. <span class="c1"># Include IP headers</span>

  2591. <span class="n">s</span><span class="o">.</span><span class="n">setsockopt</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">IPPROTO_IP</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">IP_HDRINCL</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>

  2592. 

  2593. <span class="c1"># receive all packets</span>

  2594. <span class="n">s</span><span class="o">.</span><span class="n">ioctl</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">SIO_RCVALL</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">RCVALL_ON</span><span class="p">)</span>

  2595. 

  2596. <span class="c1"># receive a packet</span>

  2597. <span class="nb">print</span><span class="p">(</span><span class="n">s</span><span class="o">.</span><span class="n">recvfrom</span><span class="p">(</span><span class="mi">65565</span><span class="p">))</span>

  2598. 

  2599. <span class="c1"># disabled promiscuous mode</span>

  2600. <span class="n">s</span><span class="o">.</span><span class="n">ioctl</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">SIO_RCVALL</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">RCVALL_OFF</span><span class="p">)</span>

  2601. </pre></div>

  2602. </div>

  2603. <p>The next example shows how to use the socket interface to communicate to a CAN

  2604. network using the raw socket protocol. To use CAN with the broadcast

  2605. manager protocol instead, open a socket with:</p>

  2606. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_CAN</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_DGRAM</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">CAN_BCM</span><span class="p">)</span>

  2607. </pre></div>

  2608. </div>

  2609. <p>After binding (<code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_RAW</span></code>) or connecting (<a class="reference internal" href="#socket.CAN_BCM" title="socket.CAN_BCM"><code class="xref py py-const docutils literal notranslate"><span class="pre">CAN_BCM</span></code></a>) the socket, you

  2610. can use the <a class="reference internal" href="#socket.socket.send" title="socket.socket.send"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.send()</span></code></a> and <a class="reference internal" href="#socket.socket.recv" title="socket.socket.recv"><code class="xref py py-meth docutils literal notranslate"><span class="pre">socket.recv()</span></code></a> operations (and

  2611. their counterparts) on the socket object as usual.</p>

  2612. <p>This last example might require special privileges:</p>

  2613. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">socket</span>

  2614. <span class="kn">import</span> <span class="nn">struct</span>

  2615. 

  2616. 

  2617. <span class="c1"># CAN frame packing/unpacking (see &#39;struct can_frame&#39; in &lt;linux/can.h&gt;)</span>

  2618. 

  2619. <span class="n">can_frame_fmt</span> <span class="o">=</span> <span class="s2">&quot;=IB3x8s&quot;</span>

  2620. <span class="n">can_frame_size</span> <span class="o">=</span> <span class="n">struct</span><span class="o">.</span><span class="n">calcsize</span><span class="p">(</span><span class="n">can_frame_fmt</span><span class="p">)</span>

  2621. 

  2622. <span class="k">def</span> <span class="nf">build_can_frame</span><span class="p">(</span><span class="n">can_id</span><span class="p">,</span> <span class="n">data</span><span class="p">):</span>

  2623.     <span class="n">can_dlc</span> <span class="o">=</span> <span class="nb">len</span><span class="p">(</span><span class="n">data</span><span class="p">)</span>

  2624.     <span class="n">data</span> <span class="o">=</span> <span class="n">data</span><span class="o">.</span><span class="n">ljust</span><span class="p">(</span><span class="mi">8</span><span class="p">,</span> <span class="sa">b</span><span class="s1">&#39;</span><span class="se">\x00</span><span class="s1">&#39;</span><span class="p">)</span>

  2625.     <span class="k">return</span> <span class="n">struct</span><span class="o">.</span><span class="n">pack</span><span class="p">(</span><span class="n">can_frame_fmt</span><span class="p">,</span> <span class="n">can_id</span><span class="p">,</span> <span class="n">can_dlc</span><span class="p">,</span> <span class="n">data</span><span class="p">)</span>

  2626. 

  2627. <span class="k">def</span> <span class="nf">dissect_can_frame</span><span class="p">(</span><span class="n">frame</span><span class="p">):</span>

  2628.     <span class="n">can_id</span><span class="p">,</span> <span class="n">can_dlc</span><span class="p">,</span> <span class="n">data</span> <span class="o">=</span> <span class="n">struct</span><span class="o">.</span><span class="n">unpack</span><span class="p">(</span><span class="n">can_frame_fmt</span><span class="p">,</span> <span class="n">frame</span><span class="p">)</span>

  2629.     <span class="k">return</span> <span class="p">(</span><span class="n">can_id</span><span class="p">,</span> <span class="n">can_dlc</span><span class="p">,</span> <span class="n">data</span><span class="p">[:</span><span class="n">can_dlc</span><span class="p">])</span>

  2630. 

  2631. 

  2632. <span class="c1"># create a raw socket and bind it to the &#39;vcan0&#39; interface</span>

  2633. <span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_CAN</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_RAW</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">CAN_RAW</span><span class="p">)</span>

  2634. <span class="n">s</span><span class="o">.</span><span class="n">bind</span><span class="p">((</span><span class="s1">&#39;vcan0&#39;</span><span class="p">,))</span>

  2635. 

  2636. <span class="k">while</span> <span class="kc">True</span><span class="p">:</span>

  2637.     <span class="n">cf</span><span class="p">,</span> <span class="n">addr</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">recvfrom</span><span class="p">(</span><span class="n">can_frame_size</span><span class="p">)</span>

  2638. 

  2639.     <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Received: can_id=</span><span class="si">%x</span><span class="s1">, can_dlc=</span><span class="si">%x</span><span class="s1">, data=</span><span class="si">%s</span><span class="s1">&#39;</span> <span class="o">%</span> <span class="n">dissect_can_frame</span><span class="p">(</span><span class="n">cf</span><span class="p">))</span>

  2640. 

  2641.     <span class="k">try</span><span class="p">:</span>

  2642.         <span class="n">s</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">cf</span><span class="p">)</span>

  2643.     <span class="k">except</span> <span class="ne">OSError</span><span class="p">:</span>

  2644.         <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Error sending CAN frame&#39;</span><span class="p">)</span>

  2645. 

  2646.     <span class="k">try</span><span class="p">:</span>

  2647.         <span class="n">s</span><span class="o">.</span><span class="n">send</span><span class="p">(</span><span class="n">build_can_frame</span><span class="p">(</span><span class="mh">0x01</span><span class="p">,</span> <span class="sa">b</span><span class="s1">&#39;</span><span class="se">\x01\x02\x03</span><span class="s1">&#39;</span><span class="p">))</span>

  2648.     <span class="k">except</span> <span class="ne">OSError</span><span class="p">:</span>

  2649.         <span class="nb">print</span><span class="p">(</span><span class="s1">&#39;Error sending CAN frame&#39;</span><span class="p">)</span>

  2650. </pre></div>

  2651. </div>

  2652. <p>Running an example several times with too small delay between executions, could

  2653. lead to this error:</p>

  2654. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="ne">OSError</span><span class="p">:</span> <span class="p">[</span><span class="n">Errno</span> <span class="mi">98</span><span class="p">]</span> <span class="n">Address</span> <span class="n">already</span> <span class="ow">in</span> <span class="n">use</span>

  2655. </pre></div>

  2656. </div>

  2657. <p>This is because the previous execution has left the socket in a <code class="docutils literal notranslate"><span class="pre">TIME_WAIT</span></code>

  2658. state, and can’t be immediately reused.</p>

  2659. <p>There is a <a class="reference internal" href="#module-socket" title="socket: Low-level networking interface."><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code></a> flag to set, in order to prevent this,

  2660. <code class="xref py py-const docutils literal notranslate"><span class="pre">socket.SO_REUSEADDR</span></code>:</p>

  2661. <div class="highlight-python3 notranslate"><div class="highlight"><pre><span></span><span class="n">s</span> <span class="o">=</span> <span class="n">socket</span><span class="o">.</span><span class="n">socket</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">AF_INET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SOCK_STREAM</span><span class="p">)</span>

  2662. <span class="n">s</span><span class="o">.</span><span class="n">setsockopt</span><span class="p">(</span><span class="n">socket</span><span class="o">.</span><span class="n">SOL_SOCKET</span><span class="p">,</span> <span class="n">socket</span><span class="o">.</span><span class="n">SO_REUSEADDR</span><span class="p">,</span> <span class="mi">1</span><span class="p">)</span>

  2663. <span class="n">s</span><span class="o">.</span><span class="n">bind</span><span class="p">((</span><span class="n">HOST</span><span class="p">,</span> <span class="n">PORT</span><span class="p">))</span>

  2664. </pre></div>

  2665. </div>

  2666. <p>the <code class="xref py py-data docutils literal notranslate"><span class="pre">SO_REUSEADDR</span></code> flag tells the kernel to reuse a local socket in

  2667. <code class="docutils literal notranslate"><span class="pre">TIME_WAIT</span></code> state, without waiting for its natural timeout to expire.</p>

  2668. <div class="admonition seealso">

  2669. <p class="admonition-title">See also</p>

  2670. <p>For an introduction to socket programming (in C), see the following papers:</p>

  2671. <ul class="simple">

  2672. <li><p><em>An Introductory 4.3BSD Interprocess Communication Tutorial</em>, by Stuart Sechrest</p></li>

  2673. <li><p><em>An Advanced 4.3BSD Interprocess Communication Tutorial</em>, by Samuel J.  Leffler et

  2674. al,</p></li>

  2675. </ul>

  2676. <p>both in the UNIX Programmer’s Manual, Supplementary Documents 1 (sections

  2677. PS1:7 and PS1:8).  The platform-specific reference material for the various

  2678. socket-related system calls are also a valuable source of information on the

  2679. details of socket semantics.  For Unix, refer to the manual pages; for Windows,

  2680. see the WinSock (or Winsock 2) specification.  For IPv6-ready APIs, readers may

  2681. want to refer to <span class="target" id="index-15"></span><a class="rfc reference external" href="https://datatracker.ietf.org/doc/html/rfc3493.html"><strong>RFC 3493</strong></a> titled Basic Socket Interface Extensions for IPv6.</p>

  2682. </div>

  2683. </section>

  2684. </section>

  2685. 

  2686. 

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  2688.           </div>

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  2691.       <div class="sphinxsidebar" role="navigation" aria-label="main navigation">

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  2693.   <div>

  2694.     <h3><a href="../contents.html">Table of Contents</a></h3>

  2695.     <ul>

  2696. <li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate"><span class="pre">socket</span></code> — Low-level networking interface</a><ul>

  2697. <li><a class="reference internal" href="#socket-families">Socket families</a></li>

  2698. <li><a class="reference internal" href="#module-contents">Module contents</a><ul>

  2699. <li><a class="reference internal" href="#exceptions">Exceptions</a></li>

  2700. <li><a class="reference internal" href="#constants">Constants</a></li>

  2701. <li><a class="reference internal" href="#functions">Functions</a><ul>

  2702. <li><a class="reference internal" href="#creating-sockets">Creating sockets</a></li>

  2703. <li><a class="reference internal" href="#other-functions">Other functions</a></li>

  2704. </ul>

  2705. </li>

  2706. </ul>

  2707. </li>

  2708. <li><a class="reference internal" href="#socket-objects">Socket Objects</a></li>

  2709. <li><a class="reference internal" href="#notes-on-socket-timeouts">Notes on socket timeouts</a><ul>

  2710. <li><a class="reference internal" href="#timeouts-and-the-connect-method">Timeouts and the <code class="docutils literal notranslate"><span class="pre">connect</span></code> method</a></li>

  2711. <li><a class="reference internal" href="#timeouts-and-the-accept-method">Timeouts and the <code class="docutils literal notranslate"><span class="pre">accept</span></code> method</a></li>

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  2713. </li>

  2714. <li><a class="reference internal" href="#example">Example</a></li>

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