/Doc/library/socket.rst
ReStructuredText | 1515 lines | 1053 code | 462 blank | 0 comment | 0 complexity | 9380a42050c970265eb5cada479fb2c2 MD5 | raw file
Large files files are truncated, but you can click here to view the full file
1:mod:`socket` --- Low-level networking interface 2================================================ 3 4.. module:: socket 5 :synopsis: Low-level networking interface. 6 7 8This module provides access to the BSD *socket* interface. It is available on 9all modern Unix systems, Windows, MacOS, OS/2, and probably additional 10platforms. 11 12.. note:: 13 14 Some behavior may be platform dependent, since calls are made to the operating 15 system socket APIs. 16 17.. index:: object: socket 18 19The Python interface is a straightforward transliteration of the Unix system 20call and library interface for sockets to Python's object-oriented style: the 21:func:`.socket` function returns a :dfn:`socket object` whose methods implement 22the various socket system calls. Parameter types are somewhat higher-level than 23in the C interface: as with :meth:`read` and :meth:`write` operations on Python 24files, buffer allocation on receive operations is automatic, and buffer length 25is implicit on send operations. 26 27 28.. seealso:: 29 30 Module :mod:`socketserver` 31 Classes that simplify writing network servers. 32 33 Module :mod:`ssl` 34 A TLS/SSL wrapper for socket objects. 35 36 37Socket families 38--------------- 39 40Depending on the system and the build options, various socket families 41are supported by this module. 42 43The address format required by a particular socket object is automatically 44selected based on the address family specified when the socket object was 45created. Socket addresses are represented as follows: 46 47- The address of an :const:`AF_UNIX` socket bound to a file system node 48 is represented as a string, using the file system encoding and the 49 ``'surrogateescape'`` error handler (see :pep:`383`). An address in 50 Linux's abstract namespace is returned as a :class:`bytes` object with 51 an initial null byte; note that sockets in this namespace can 52 communicate with normal file system sockets, so programs intended to 53 run on Linux may need to deal with both types of address. A string or 54 :class:`bytes` object can be used for either type of address when 55 passing it as an argument. 56 57 .. versionchanged:: 3.3 58 Previously, :const:`AF_UNIX` socket paths were assumed to use UTF-8 59 encoding. 60 61- A pair ``(host, port)`` is used for the :const:`AF_INET` address family, 62 where *host* is a string representing either a hostname in Internet domain 63 notation like ``'daring.cwi.nl'`` or an IPv4 address like ``'100.50.200.5'``, 64 and *port* is an integer. 65 66- For :const:`AF_INET6` address family, a four-tuple ``(host, port, flowinfo, 67 scopeid)`` is used, where *flowinfo* and *scopeid* represent the ``sin6_flowinfo`` 68 and ``sin6_scope_id`` members in :const:`struct sockaddr_in6` in C. For 69 :mod:`socket` module methods, *flowinfo* and *scopeid* can be omitted just for 70 backward compatibility. Note, however, omission of *scopeid* can cause problems 71 in manipulating scoped IPv6 addresses. 72 73- :const:`AF_NETLINK` sockets are represented as pairs ``(pid, groups)``. 74 75- Linux-only support for TIPC is available using the :const:`AF_TIPC` 76 address family. TIPC is an open, non-IP based networked protocol designed 77 for use in clustered computer environments. Addresses are represented by a 78 tuple, and the fields depend on the address type. The general tuple form is 79 ``(addr_type, v1, v2, v3 [, scope])``, where: 80 81 - *addr_type* is one of :const:`TIPC_ADDR_NAMESEQ`, :const:`TIPC_ADDR_NAME`, 82 or :const:`TIPC_ADDR_ID`. 83 - *scope* is one of :const:`TIPC_ZONE_SCOPE`, :const:`TIPC_CLUSTER_SCOPE`, and 84 :const:`TIPC_NODE_SCOPE`. 85 - If *addr_type* is :const:`TIPC_ADDR_NAME`, then *v1* is the server type, *v2* is 86 the port identifier, and *v3* should be 0. 87 88 If *addr_type* is :const:`TIPC_ADDR_NAMESEQ`, then *v1* is the server type, *v2* 89 is the lower port number, and *v3* is the upper port number. 90 91 If *addr_type* is :const:`TIPC_ADDR_ID`, then *v1* is the node, *v2* is the 92 reference, and *v3* should be set to 0. 93 94 If *addr_type* is :const:`TIPC_ADDR_ID`, then *v1* is the node, *v2* is the 95 reference, and *v3* should be set to 0. 96 97- A tuple ``(interface, )`` is used for the :const:`AF_CAN` address family, 98 where *interface* is a string representing a network interface name like 99 ``'can0'``. The network interface name ``''`` can be used to receive packets 100 from all network interfaces of this family. 101 102- A string or a tuple ``(id, unit)`` is used for the :const:`SYSPROTO_CONTROL` 103 protocol of the :const:`PF_SYSTEM` family. The string is the name of a 104 kernel control using a dynamically-assigned ID. The tuple can be used if ID 105 and unit number of the kernel control are known or if a registered ID is 106 used. 107 108 .. versionadded:: 3.3 109 110- Certain other address families (:const:`AF_BLUETOOTH`, :const:`AF_PACKET`, 111 :const:`AF_CAN`) support specific representations. 112 113 .. XXX document them! 114 115For IPv4 addresses, two special forms are accepted instead of a host address: 116the empty string represents :const:`INADDR_ANY`, and the string 117``'<broadcast>'`` represents :const:`INADDR_BROADCAST`. This behavior is not 118compatible with IPv6, therefore, you may want to avoid these if you intend 119to support IPv6 with your Python programs. 120 121If you use a hostname in the *host* portion of IPv4/v6 socket address, the 122program may show a nondeterministic behavior, as Python uses the first address 123returned from the DNS resolution. The socket address will be resolved 124differently into an actual IPv4/v6 address, depending on the results from DNS 125resolution and/or the host configuration. For deterministic behavior use a 126numeric address in *host* portion. 127 128All errors raise exceptions. The normal exceptions for invalid argument types 129and out-of-memory conditions can be raised; starting from Python 3.3, errors 130related to socket or address semantics raise :exc:`OSError` or one of its 131subclasses (they used to raise :exc:`socket.error`). 132 133Non-blocking mode is supported through :meth:`~socket.setblocking`. A 134generalization of this based on timeouts is supported through 135:meth:`~socket.settimeout`. 136 137 138Module contents 139--------------- 140 141The module :mod:`socket` exports the following elements. 142 143 144Exceptions 145^^^^^^^^^^ 146 147.. exception:: error 148 149 A deprecated alias of :exc:`OSError`. 150 151 .. versionchanged:: 3.3 152 Following :pep:`3151`, this class was made an alias of :exc:`OSError`. 153 154 155.. exception:: herror 156 157 A subclass of :exc:`OSError`, this exception is raised for 158 address-related errors, i.e. for functions that use *h_errno* in the POSIX 159 C API, including :func:`gethostbyname_ex` and :func:`gethostbyaddr`. 160 The accompanying value is a pair ``(h_errno, string)`` representing an 161 error returned by a library call. *h_errno* is a numeric value, while 162 *string* represents the description of *h_errno*, as returned by the 163 :c:func:`hstrerror` C function. 164 165 .. versionchanged:: 3.3 166 This class was made a subclass of :exc:`OSError`. 167 168.. exception:: gaierror 169 170 A subclass of :exc:`OSError`, this exception is raised for 171 address-related errors by :func:`getaddrinfo` and :func:`getnameinfo`. 172 The accompanying value is a pair ``(error, string)`` representing an error 173 returned by a library call. *string* represents the description of 174 *error*, as returned by the :c:func:`gai_strerror` C function. The 175 numeric *error* value will match one of the :const:`EAI_\*` constants 176 defined in this module. 177 178 .. versionchanged:: 3.3 179 This class was made a subclass of :exc:`OSError`. 180 181.. exception:: timeout 182 183 A subclass of :exc:`OSError`, this exception is raised when a timeout 184 occurs on a socket which has had timeouts enabled via a prior call to 185 :meth:`~socket.settimeout` (or implicitly through 186 :func:`~socket.setdefaulttimeout`). The accompanying value is a string 187 whose value is currently always "timed out". 188 189 .. versionchanged:: 3.3 190 This class was made a subclass of :exc:`OSError`. 191 192 193Constants 194^^^^^^^^^ 195 196.. data:: AF_UNIX 197 AF_INET 198 AF_INET6 199 200 These constants represent the address (and protocol) families, used for the 201 first argument to :func:`.socket`. If the :const:`AF_UNIX` constant is not 202 defined then this protocol is unsupported. More constants may be available 203 depending on the system. 204 205 206.. data:: SOCK_STREAM 207 SOCK_DGRAM 208 SOCK_RAW 209 SOCK_RDM 210 SOCK_SEQPACKET 211 212 These constants represent the socket types, used for the second argument to 213 :func:`.socket`. More constants may be available depending on the system. 214 (Only :const:`SOCK_STREAM` and :const:`SOCK_DGRAM` appear to be generally 215 useful.) 216 217.. data:: SOCK_CLOEXEC 218 SOCK_NONBLOCK 219 220 These two constants, if defined, can be combined with the socket types and 221 allow you to set some flags atomically (thus avoiding possible race 222 conditions and the need for separate calls). 223 224 .. seealso:: 225 226 `Secure File Descriptor Handling <http://udrepper.livejournal.com/20407.html>`_ 227 for a more thorough explanation. 228 229 Availability: Linux >= 2.6.27. 230 231 .. versionadded:: 3.2 232 233.. data:: SO_* 234 SOMAXCONN 235 MSG_* 236 SOL_* 237 SCM_* 238 IPPROTO_* 239 IPPORT_* 240 INADDR_* 241 IP_* 242 IPV6_* 243 EAI_* 244 AI_* 245 NI_* 246 TCP_* 247 248 Many constants of these forms, documented in the Unix documentation on sockets 249 and/or the IP protocol, are also defined in the socket module. They are 250 generally used in arguments to the :meth:`setsockopt` and :meth:`getsockopt` 251 methods of socket objects. In most cases, only those symbols that are defined 252 in the Unix header files are defined; for a few symbols, default values are 253 provided. 254 255.. data:: AF_CAN 256 PF_CAN 257 SOL_CAN_* 258 CAN_* 259 260 Many constants of these forms, documented in the Linux documentation, are 261 also defined in the socket module. 262 263 Availability: Linux >= 2.6.25. 264 265 .. versionadded:: 3.3 266 267.. data:: CAN_BCM 268 CAN_BCM_* 269 270 CAN_BCM, in the CAN protocol family, is the broadcast manager (BCM) protocol. 271 Broadcast manager constants, documented in the Linux documentation, are also 272 defined in the socket module. 273 274 Availability: Linux >= 2.6.25. 275 276 .. versionadded:: 3.4 277 278.. data:: AF_RDS 279 PF_RDS 280 SOL_RDS 281 RDS_* 282 283 Many constants of these forms, documented in the Linux documentation, are 284 also defined in the socket module. 285 286 Availability: Linux >= 2.6.30. 287 288 .. versionadded:: 3.3 289 290 291.. data:: SIO_* 292 RCVALL_* 293 294 Constants for Windows' WSAIoctl(). The constants are used as arguments to the 295 :meth:`~socket.socket.ioctl` method of socket objects. 296 297 298.. data:: TIPC_* 299 300 TIPC related constants, matching the ones exported by the C socket API. See 301 the TIPC documentation for more information. 302 303.. data:: AF_LINK 304 305 Availability: BSD, OSX. 306 307 .. versionadded:: 3.4 308 309.. data:: has_ipv6 310 311 This constant contains a boolean value which indicates if IPv6 is supported on 312 this platform. 313 314 315Functions 316^^^^^^^^^ 317 318Creating sockets 319'''''''''''''''' 320 321The following functions all create :ref:`socket objects <socket-objects>`. 322 323 324.. function:: socket(family=AF_INET, type=SOCK_STREAM, proto=0, fileno=None) 325 326 Create a new socket using the given address family, socket type and protocol 327 number. The address family should be :const:`AF_INET` (the default), 328 :const:`AF_INET6`, :const:`AF_UNIX`, :const:`AF_CAN` or :const:`AF_RDS`. The 329 socket type should be :const:`SOCK_STREAM` (the default), 330 :const:`SOCK_DGRAM`, :const:`SOCK_RAW` or perhaps one of the other ``SOCK_`` 331 constants. The protocol number is usually zero and may be omitted or in the 332 case where the address family is :const:`AF_CAN` the protocol should be one 333 of :const:`CAN_RAW` or :const:`CAN_BCM`. 334 335 The newly created socket is :ref:`non-inheritable <fd_inheritance>`. 336 337 .. versionchanged:: 3.3 338 The AF_CAN family was added. 339 The AF_RDS family was added. 340 341 .. versionchanged:: 3.4 342 The CAN_BCM protocol was added. 343 344 .. versionchanged:: 3.4 345 The returned socket is now non-inheritable. 346 347 348.. function:: socketpair([family[, type[, proto]]]) 349 350 Build a pair of connected socket objects using the given address family, socket 351 type, and protocol number. Address family, socket type, and protocol number are 352 as for the :func:`.socket` function above. The default family is :const:`AF_UNIX` 353 if defined on the platform; otherwise, the default is :const:`AF_INET`. 354 Availability: Unix. 355 356 The newly created sockets are :ref:`non-inheritable <fd_inheritance>`. 357 358 .. versionchanged:: 3.2 359 The returned socket objects now support the whole socket API, rather 360 than a subset. 361 362 .. versionchanged:: 3.4 363 The returned sockets are now non-inheritable. 364 365 366.. function:: create_connection(address[, timeout[, source_address]]) 367 368 Connect to a TCP service listening on the Internet *address* (a 2-tuple 369 ``(host, port)``), and return the socket object. This is a higher-level 370 function than :meth:`socket.connect`: if *host* is a non-numeric hostname, 371 it will try to resolve it for both :data:`AF_INET` and :data:`AF_INET6`, 372 and then try to connect to all possible addresses in turn until a 373 connection succeeds. This makes it easy to write clients that are 374 compatible to both IPv4 and IPv6. 375 376 Passing the optional *timeout* parameter will set the timeout on the 377 socket instance before attempting to connect. If no *timeout* is 378 supplied, the global default timeout setting returned by 379 :func:`getdefaulttimeout` is used. 380 381 If supplied, *source_address* must be a 2-tuple ``(host, port)`` for the 382 socket to bind to as its source address before connecting. If host or port 383 are '' or 0 respectively the OS default behavior will be used. 384 385 .. versionchanged:: 3.2 386 *source_address* was added. 387 388 .. versionchanged:: 3.2 389 support for the :keyword:`with` statement was added. 390 391 392.. function:: fromfd(fd, family, type, proto=0) 393 394 Duplicate the file descriptor *fd* (an integer as returned by a file object's 395 :meth:`fileno` method) and build a socket object from the result. Address 396 family, socket type and protocol number are as for the :func:`.socket` function 397 above. The file descriptor should refer to a socket, but this is not checked --- 398 subsequent operations on the object may fail if the file descriptor is invalid. 399 This function is rarely needed, but can be used to get or set socket options on 400 a socket passed to a program as standard input or output (such as a server 401 started by the Unix inet daemon). The socket is assumed to be in blocking mode. 402 403 The newly created socket is :ref:`non-inheritable <fd_inheritance>`. 404 405 .. versionchanged:: 3.4 406 The returned socket is now non-inheritable. 407 408 409.. function:: fromshare(data) 410 411 Instantiate a socket from data obtained from the :meth:`socket.share` 412 method. The socket is assumed to be in blocking mode. 413 414 Availability: Windows. 415 416 .. versionadded:: 3.3 417 418 419.. data:: SocketType 420 421 This is a Python type object that represents the socket object type. It is the 422 same as ``type(socket(...))``. 423 424 425Other functions 426''''''''''''''' 427 428The :mod:`socket` module also offers various network-related services: 429 430 431.. function:: getaddrinfo(host, port, family=0, type=0, proto=0, flags=0) 432 433 Translate the *host*/*port* argument into a sequence of 5-tuples that contain 434 all the necessary arguments for creating a socket connected to that service. 435 *host* is a domain name, a string representation of an IPv4/v6 address 436 or ``None``. *port* is a string service name such as ``'http'``, a numeric 437 port number or ``None``. By passing ``None`` as the value of *host* 438 and *port*, you can pass ``NULL`` to the underlying C API. 439 440 The *family*, *type* and *proto* arguments can be optionally specified 441 in order to narrow the list of addresses returned. Passing zero as a 442 value for each of these arguments selects the full range of results. 443 The *flags* argument can be one or several of the ``AI_*`` constants, 444 and will influence how results are computed and returned. 445 For example, :const:`AI_NUMERICHOST` will disable domain name resolution 446 and will raise an error if *host* is a domain name. 447 448 The function returns a list of 5-tuples with the following structure: 449 450 ``(family, type, proto, canonname, sockaddr)`` 451 452 In these tuples, *family*, *type*, *proto* are all integers and are 453 meant to be passed to the :func:`.socket` function. *canonname* will be 454 a string representing the canonical name of the *host* if 455 :const:`AI_CANONNAME` is part of the *flags* argument; else *canonname* 456 will be empty. *sockaddr* is a tuple describing a socket address, whose 457 format depends on the returned *family* (a ``(address, port)`` 2-tuple for 458 :const:`AF_INET`, a ``(address, port, flow info, scope id)`` 4-tuple for 459 :const:`AF_INET6`), and is meant to be passed to the :meth:`socket.connect` 460 method. 461 462 The following example fetches address information for a hypothetical TCP 463 connection to ``www.python.org`` on port 80 (results may differ on your 464 system if IPv6 isn't enabled):: 465 466 >>> socket.getaddrinfo("www.python.org", 80, proto=socket.SOL_TCP) 467 [(2, 1, 6, '', ('82.94.164.162', 80)), 468 (10, 1, 6, '', ('2001:888:2000:d::a2', 80, 0, 0))] 469 470 .. versionchanged:: 3.2 471 parameters can now be passed as single keyword arguments. 472 473.. function:: getfqdn([name]) 474 475 Return a fully qualified domain name for *name*. If *name* is omitted or empty, 476 it is interpreted as the local host. To find the fully qualified name, the 477 hostname returned by :func:`gethostbyaddr` is checked, followed by aliases for the 478 host, if available. The first name which includes a period is selected. In 479 case no fully qualified domain name is available, the hostname as returned by 480 :func:`gethostname` is returned. 481 482 483.. function:: gethostbyname(hostname) 484 485 Translate a host name to IPv4 address format. The IPv4 address is returned as a 486 string, such as ``'100.50.200.5'``. If the host name is an IPv4 address itself 487 it is returned unchanged. See :func:`gethostbyname_ex` for a more complete 488 interface. :func:`gethostbyname` does not support IPv6 name resolution, and 489 :func:`getaddrinfo` should be used instead for IPv4/v6 dual stack support. 490 491 492.. function:: gethostbyname_ex(hostname) 493 494 Translate a host name to IPv4 address format, extended interface. Return a 495 triple ``(hostname, aliaslist, ipaddrlist)`` where *hostname* is the primary 496 host name responding to the given *ip_address*, *aliaslist* is a (possibly 497 empty) list of alternative host names for the same address, and *ipaddrlist* is 498 a list of IPv4 addresses for the same interface on the same host (often but not 499 always a single address). :func:`gethostbyname_ex` does not support IPv6 name 500 resolution, and :func:`getaddrinfo` should be used instead for IPv4/v6 dual 501 stack support. 502 503 504.. function:: gethostname() 505 506 Return a string containing the hostname of the machine where the Python 507 interpreter is currently executing. 508 509 If you want to know the current machine's IP address, you may want to use 510 ``gethostbyname(gethostname())``. This operation assumes that there is a 511 valid address-to-host mapping for the host, and the assumption does not 512 always hold. 513 514 Note: :func:`gethostname` doesn't always return the fully qualified domain 515 name; use ``getfqdn()`` (see above). 516 517 518.. function:: gethostbyaddr(ip_address) 519 520 Return a triple ``(hostname, aliaslist, ipaddrlist)`` where *hostname* is the 521 primary host name responding to the given *ip_address*, *aliaslist* is a 522 (possibly empty) list of alternative host names for the same address, and 523 *ipaddrlist* is a list of IPv4/v6 addresses for the same interface on the same 524 host (most likely containing only a single address). To find the fully qualified 525 domain name, use the function :func:`getfqdn`. :func:`gethostbyaddr` supports 526 both IPv4 and IPv6. 527 528 529.. function:: getnameinfo(sockaddr, flags) 530 531 Translate a socket address *sockaddr* into a 2-tuple ``(host, port)``. Depending 532 on the settings of *flags*, the result can contain a fully-qualified domain name 533 or numeric address representation in *host*. Similarly, *port* can contain a 534 string port name or a numeric port number. 535 536 537.. function:: getprotobyname(protocolname) 538 539 Translate an Internet protocol name (for example, ``'icmp'``) to a constant 540 suitable for passing as the (optional) third argument to the :func:`.socket` 541 function. This is usually only needed for sockets opened in "raw" mode 542 (:const:`SOCK_RAW`); for the normal socket modes, the correct protocol is chosen 543 automatically if the protocol is omitted or zero. 544 545 546.. function:: getservbyname(servicename[, protocolname]) 547 548 Translate an Internet service name and protocol name to a port number for that 549 service. The optional protocol name, if given, should be ``'tcp'`` or 550 ``'udp'``, otherwise any protocol will match. 551 552 553.. function:: getservbyport(port[, protocolname]) 554 555 Translate an Internet port number and protocol name to a service name for that 556 service. The optional protocol name, if given, should be ``'tcp'`` or 557 ``'udp'``, otherwise any protocol will match. 558 559 560.. function:: ntohl(x) 561 562 Convert 32-bit positive integers from network to host byte order. On machines 563 where the host byte order is the same as network byte order, this is a no-op; 564 otherwise, it performs a 4-byte swap operation. 565 566 567.. function:: ntohs(x) 568 569 Convert 16-bit positive integers from network to host byte order. On machines 570 where the host byte order is the same as network byte order, this is a no-op; 571 otherwise, it performs a 2-byte swap operation. 572 573 574.. function:: htonl(x) 575 576 Convert 32-bit positive integers from host to network byte order. On machines 577 where the host byte order is the same as network byte order, this is a no-op; 578 otherwise, it performs a 4-byte swap operation. 579 580 581.. function:: htons(x) 582 583 Convert 16-bit positive integers from host to network byte order. On machines 584 where the host byte order is the same as network byte order, this is a no-op; 585 otherwise, it performs a 2-byte swap operation. 586 587 588.. function:: inet_aton(ip_string) 589 590 Convert an IPv4 address from dotted-quad string format (for example, 591 '123.45.67.89') to 32-bit packed binary format, as a bytes object four characters in 592 length. This is useful when conversing with a program that uses the standard C 593 library and needs objects of type :c:type:`struct in_addr`, which is the C type 594 for the 32-bit packed binary this function returns. 595 596 :func:`inet_aton` also accepts strings with less than three dots; see the 597 Unix manual page :manpage:`inet(3)` for details. 598 599 If the IPv4 address string passed to this function is invalid, 600 :exc:`OSError` will be raised. Note that exactly what is valid depends on 601 the underlying C implementation of :c:func:`inet_aton`. 602 603 :func:`inet_aton` does not support IPv6, and :func:`inet_pton` should be used 604 instead for IPv4/v6 dual stack support. 605 606 607.. function:: inet_ntoa(packed_ip) 608 609 Convert a 32-bit packed IPv4 address (a bytes object four characters in 610 length) to its standard dotted-quad string representation (for example, 611 '123.45.67.89'). This is useful when conversing with a program that uses the 612 standard C library and needs objects of type :c:type:`struct in_addr`, which 613 is the C type for the 32-bit packed binary data this function takes as an 614 argument. 615 616 If the byte sequence passed to this function is not exactly 4 bytes in 617 length, :exc:`OSError` will be raised. :func:`inet_ntoa` does not 618 support IPv6, and :func:`inet_ntop` should be used instead for IPv4/v6 dual 619 stack support. 620 621 622.. function:: inet_pton(address_family, ip_string) 623 624 Convert an IP address from its family-specific string format to a packed, 625 binary format. :func:`inet_pton` is useful when a library or network protocol 626 calls for an object of type :c:type:`struct in_addr` (similar to 627 :func:`inet_aton`) or :c:type:`struct in6_addr`. 628 629 Supported values for *address_family* are currently :const:`AF_INET` and 630 :const:`AF_INET6`. If the IP address string *ip_string* is invalid, 631 :exc:`OSError` will be raised. Note that exactly what is valid depends on 632 both the value of *address_family* and the underlying implementation of 633 :c:func:`inet_pton`. 634 635 Availability: Unix (maybe not all platforms), Windows. 636 637 638.. function:: inet_ntop(address_family, packed_ip) 639 640 Convert a packed IP address (a bytes object of some number of characters) to its 641 standard, family-specific string representation (for example, ``'7.10.0.5'`` or 642 ``'5aef:2b::8'``). :func:`inet_ntop` is useful when a library or network protocol 643 returns an object of type :c:type:`struct in_addr` (similar to :func:`inet_ntoa`) 644 or :c:type:`struct in6_addr`. 645 646 Supported values for *address_family* are currently :const:`AF_INET` and 647 :const:`AF_INET6`. If the string *packed_ip* is not the correct length for the 648 specified address family, :exc:`ValueError` will be raised. A 649 :exc:`OSError` is raised for errors from the call to :func:`inet_ntop`. 650 651 Availability: Unix (maybe not all platforms), Windows. 652 653 654.. 655 XXX: Are sendmsg(), recvmsg() and CMSG_*() available on any 656 non-Unix platforms? The old (obsolete?) 4.2BSD form of the 657 interface, in which struct msghdr has no msg_control or 658 msg_controllen members, is not currently supported. 659 660.. function:: CMSG_LEN(length) 661 662 Return the total length, without trailing padding, of an ancillary 663 data item with associated data of the given *length*. This value 664 can often be used as the buffer size for :meth:`~socket.recvmsg` to 665 receive a single item of ancillary data, but :rfc:`3542` requires 666 portable applications to use :func:`CMSG_SPACE` and thus include 667 space for padding, even when the item will be the last in the 668 buffer. Raises :exc:`OverflowError` if *length* is outside the 669 permissible range of values. 670 671 Availability: most Unix platforms, possibly others. 672 673 .. versionadded:: 3.3 674 675 676.. function:: CMSG_SPACE(length) 677 678 Return the buffer size needed for :meth:`~socket.recvmsg` to 679 receive an ancillary data item with associated data of the given 680 *length*, along with any trailing padding. The buffer space needed 681 to receive multiple items is the sum of the :func:`CMSG_SPACE` 682 values for their associated data lengths. Raises 683 :exc:`OverflowError` if *length* is outside the permissible range 684 of values. 685 686 Note that some systems might support ancillary data without 687 providing this function. Also note that setting the buffer size 688 using the results of this function may not precisely limit the 689 amount of ancillary data that can be received, since additional 690 data may be able to fit into the padding area. 691 692 Availability: most Unix platforms, possibly others. 693 694 .. versionadded:: 3.3 695 696 697.. function:: getdefaulttimeout() 698 699 Return the default timeout in seconds (float) for new socket objects. A value 700 of ``None`` indicates that new socket objects have no timeout. When the socket 701 module is first imported, the default is ``None``. 702 703 704.. function:: setdefaulttimeout(timeout) 705 706 Set the default timeout in seconds (float) for new socket objects. When 707 the socket module is first imported, the default is ``None``. See 708 :meth:`~socket.settimeout` for possible values and their respective 709 meanings. 710 711 712.. function:: sethostname(name) 713 714 Set the machine's hostname to *name*. This will raise a 715 :exc:`OSError` if you don't have enough rights. 716 717 Availability: Unix. 718 719 .. versionadded:: 3.3 720 721 722.. function:: if_nameindex() 723 724 Return a list of network interface information 725 (index int, name string) tuples. 726 :exc:`OSError` if the system call fails. 727 728 Availability: Unix. 729 730 .. versionadded:: 3.3 731 732 733.. function:: if_nametoindex(if_name) 734 735 Return a network interface index number corresponding to an 736 interface name. 737 :exc:`OSError` if no interface with the given name exists. 738 739 Availability: Unix. 740 741 .. versionadded:: 3.3 742 743 744.. function:: if_indextoname(if_index) 745 746 Return a network interface name corresponding to a 747 interface index number. 748 :exc:`OSError` if no interface with the given index exists. 749 750 Availability: Unix. 751 752 .. versionadded:: 3.3 753 754 755.. _socket-objects: 756 757Socket Objects 758-------------- 759 760Socket objects have the following methods. Except for 761:meth:`~socket.makefile`, these correspond to Unix system calls applicable 762to sockets. 763 764 765.. method:: socket.accept() 766 767 Accept a connection. The socket must be bound to an address and listening for 768 connections. The return value is a pair ``(conn, address)`` where *conn* is a 769 *new* socket object usable to send and receive data on the connection, and 770 *address* is the address bound to the socket on the other end of the connection. 771 772 The newly created socket is :ref:`non-inheritable <fd_inheritance>`. 773 774 .. versionchanged:: 3.4 775 The socket is now non-inheritable. 776 777 778.. method:: socket.bind(address) 779 780 Bind the socket to *address*. The socket must not already be bound. (The format 781 of *address* depends on the address family --- see above.) 782 783 784.. method:: socket.close() 785 786 Mark the socket closed. The underlying system resource (e.g. a file 787 descriptor) is also closed when all file objects from :meth:`makefile()` 788 are closed. Once that happens, all future operations on the socket 789 object will fail. The remote end will receive no more data (after 790 queued data is flushed). 791 792 Sockets are automatically closed when they are garbage-collected, but 793 it is recommended to :meth:`close` them explicitly, or to use a 794 :keyword:`with` statement around them. 795 796 .. note:: 797 :meth:`close()` releases the resource associated with a connection but 798 does not necessarily close the connection immediately. If you want 799 to close the connection in a timely fashion, call :meth:`shutdown()` 800 before :meth:`close()`. 801 802 803.. method:: socket.connect(address) 804 805 Connect to a remote socket at *address*. (The format of *address* depends on the 806 address family --- see above.) 807 808 809.. method:: socket.connect_ex(address) 810 811 Like ``connect(address)``, but return an error indicator instead of raising an 812 exception for errors returned by the C-level :c:func:`connect` call (other 813 problems, such as "host not found," can still raise exceptions). The error 814 indicator is ``0`` if the operation succeeded, otherwise the value of the 815 :c:data:`errno` variable. This is useful to support, for example, asynchronous 816 connects. 817 818 819.. method:: socket.detach() 820 821 Put the socket object into closed state without actually closing the 822 underlying file descriptor. The file descriptor is returned, and can 823 be reused for other purposes. 824 825 .. versionadded:: 3.2 826 827 828.. method:: socket.dup() 829 830 Duplicate the socket. 831 832 The newly created socket is :ref:`non-inheritable <fd_inheritance>`. 833 834 .. versionchanged:: 3.4 835 The socket is now non-inheritable. 836 837 838.. method:: socket.fileno() 839 840 Return the socket's file descriptor (a small integer). This is useful with 841 :func:`select.select`. 842 843 Under Windows the small integer returned by this method cannot be used where a 844 file descriptor can be used (such as :func:`os.fdopen`). Unix does not have 845 this limitation. 846 847 848.. method:: socket.get_inheritable() 849 850 Get the :ref:`inheritable flag <fd_inheritance>` of the socket's file 851 descriptor or socket's handle: ``True`` if the socket can be inherited in 852 child processes, ``False`` if it cannot. 853 854 .. versionadded:: 3.4 855 856 857.. method:: socket.getpeername() 858 859 Return the remote address to which the socket is connected. This is useful to 860 find out the port number of a remote IPv4/v6 socket, for instance. (The format 861 of the address returned depends on the address family --- see above.) On some 862 systems this function is not supported. 863 864 865.. method:: socket.getsockname() 866 867 Return the socket's own address. This is useful to find out the port number of 868 an IPv4/v6 socket, for instance. (The format of the address returned depends on 869 the address family --- see above.) 870 871 872.. method:: socket.getsockopt(level, optname[, buflen]) 873 874 Return the value of the given socket option (see the Unix man page 875 :manpage:`getsockopt(2)`). The needed symbolic constants (:const:`SO_\*` etc.) 876 are defined in this module. If *buflen* is absent, an integer option is assumed 877 and its integer value is returned by the function. If *buflen* is present, it 878 specifies the maximum length of the buffer used to receive the option in, and 879 this buffer is returned as a bytes object. It is up to the caller to decode the 880 contents of the buffer (see the optional built-in module :mod:`struct` for a way 881 to decode C structures encoded as byte strings). 882 883 884.. method:: socket.gettimeout() 885 886 Return the timeout in seconds (float) associated with socket operations, 887 or ``None`` if no timeout is set. This reflects the last call to 888 :meth:`setblocking` or :meth:`settimeout`. 889 890 891.. method:: socket.ioctl(control, option) 892 893 :platform: Windows 894 895 The :meth:`ioctl` method is a limited interface to the WSAIoctl system 896 interface. Please refer to the `Win32 documentation 897 <http://msdn.microsoft.com/en-us/library/ms741621%28VS.85%29.aspx>`_ for more 898 information. 899 900 On other platforms, the generic :func:`fcntl.fcntl` and :func:`fcntl.ioctl` 901 functions may be used; they accept a socket object as their first argument. 902 903.. method:: socket.listen(backlog) 904 905 Listen for connections made to the socket. The *backlog* argument specifies the 906 maximum number of queued connections and should be at least 0; the maximum value 907 is system-dependent (usually 5), the minimum value is forced to 0. 908 909 910.. method:: socket.makefile(mode='r', buffering=None, *, encoding=None, \ 911 errors=None, newline=None) 912 913 .. index:: single: I/O control; buffering 914 915 Return a :term:`file object` associated with the socket. The exact returned 916 type depends on the arguments given to :meth:`makefile`. These arguments are 917 interpreted the same way as by the built-in :func:`open` function. 918 919 The socket must be in blocking mode; it can have a timeout, but the file 920 object's internal buffer may end up in a inconsistent state if a timeout 921 occurs. 922 923 Closing the file object returned by :meth:`makefile` won't close the 924 original socket unless all other file objects have been closed and 925 :meth:`socket.close` has been called on the socket object. 926 927 .. note:: 928 929 On Windows, the file-like object created by :meth:`makefile` cannot be 930 used where a file object with a file descriptor is expected, such as the 931 stream arguments of :meth:`subprocess.Popen`. 932 933 934.. method:: socket.recv(bufsize[, flags]) 935 936 Receive data from the socket. The return value is a bytes object representing the 937 data received. The maximum amount of data to be received at once is specified 938 by *bufsize*. See the Unix manual page :manpage:`recv(2)` for the meaning of 939 the optional argument *flags*; it defaults to zero. 940 941 .. note:: 942 943 For best match with hardware and network realities, the value of *bufsize* 944 should be a relatively small power of 2, for example, 4096. 945 946 947.. method:: socket.recvfrom(bufsize[, flags]) 948 949 Receive data from the socket. The return value is a pair ``(bytes, address)`` 950 where *bytes* is a bytes object representing the data received and *address* is the 951 address of the socket sending the data. See the Unix manual page 952 :manpage:`recv(2)` for the meaning of the optional argument *flags*; it defaults 953 to zero. (The format of *address* depends on the address family --- see above.) 954 955 956.. method:: socket.recvmsg(bufsize[, ancbufsize[, flags]]) 957 958 Receive normal data (up to *bufsize* bytes) and ancillary data from 959 the socket. The *ancbufsize* argument sets the size in bytes of 960 the internal buffer used to receive the ancillary data; it defaults 961 to 0, meaning that no ancillary data will be received. Appropriate 962 buffer sizes for ancillary data can be calculated using 963 :func:`CMSG_SPACE` or :func:`CMSG_LEN`, and items which do not fit 964 into the buffer might be truncated or discarded. The *flags* 965 argument defaults to 0 and has the same meaning as for 966 :meth:`recv`. 967 968 The return value is a 4-tuple: ``(data, ancdata, msg_flags, 969 address)``. The *data* item is a :class:`bytes` object holding the 970 non-ancillary data received. The *ancdata* item is a list of zero 971 or more tuples ``(cmsg_level, cmsg_type, cmsg_data)`` representing 972 the ancillary data (control messages) received: *cmsg_level* and 973 *cmsg_type* are integers specifying the protocol level and 974 protocol-specific type respectively, and *cmsg_data* is a 975 :class:`bytes` object holding the associated data. The *msg_flags* 976 item is the bitwise OR of various flags indicating conditions on 977 the received message; see your system documentation for details. 978 If the receiving socket is unconnected, *address* is the address of 979 the sending socket, if available; otherwise, its value is 980 unspecified. 981 982 On some systems, :meth:`sendmsg` and :meth:`recvmsg` can be used to 983 pass file descriptors between processes over an :const:`AF_UNIX` 984 socket. When this facility is used (it is often restricted to 985 :const:`SOCK_STREAM` sockets), :meth:`recvmsg` will return, in its 986 ancillary data, items of the form ``(socket.SOL_SOCKET, 987 socket.SCM_RIGHTS, fds)``, where *fds* is a :class:`bytes` object 988 representing the new file descriptors as a binary array of the 989 native C :c:type:`int` type. If :meth:`recvmsg` raises an 990 exception after the system call returns, it will first attempt to 991 close any file descriptors received via this mechanism. 992 993 Some systems do not indicate the truncated length of ancillary data 994 items which have been only partially received. If an item appears 995 to extend beyond the end of the buffer, :meth:`recvmsg` will issue 996 a :exc:`RuntimeWarning`, and will return the part of it which is 997 inside the buffer provided it has not been truncated before the 998 start of its associated data. 999 1000 On systems which support the :const:`SCM_RIGHTS` mechanism, the 1001 following function will receive up to *maxfds* file descriptors, 1002 returning the message data and a list containing the descriptors 1003 (while ignoring unexpected conditions such as unrelated control 1004 messages being received). See also :meth:`sendmsg`. :: 1005 1006 import socket, array 1007 1008 def recv_fds(sock, msglen, maxfds): 1009 fds = array.array("i") # Array of ints 1010 msg, ancdata, flags, addr = sock.recvmsg(msglen, socket.CMSG_LEN(maxfds * fds.itemsize)) 1011 for cmsg_level, cmsg_type, cmsg_data in ancdata: 1012 if (cmsg_level == socket.SOL_SOCKET and cmsg_type == socket.SCM_RIGHTS): 1013 # Append data, ignoring any truncated integers at the end. 1014 fds.fromstring(cmsg_data[:len(cmsg_data) - (len(cmsg_data) % fds.itemsize)]) 1015 return msg, list(fds) 1016 1017 Availability: most Unix platforms, possibly others. 1018 1019 .. versionadded:: 3.3 1020 1021 1022.. method:: socket.recvmsg_into(buffers[, ancbufsize[, flags]]) 1023 1024 Receive normal data and ancillary data from the socket, behaving as 1025 :meth:`recvmsg` would, but scatter the non-ancillary data into a 1026 series of buffers instead of returning a new bytes object. The 1027 *buffers* argument must be an iterable of objects that export 1028 writable buffers (e.g. :class:`bytearray` objects); these will be 1029 filled with successive chunks of the non-ancillary data until it 1030 has all been written or there are no more buffers. The operating 1031 system may set a limit (:func:`~os.sysconf` value ``SC_IOV_MAX``) 1032 on the number of buffers that can be used. The *ancbufsize* and 1033 *flags* arguments have the same meaning as for :meth:`recvmsg`. 1034 1035 The return value is a 4-tuple: ``(nbytes, ancdata, msg_flags, 1036 address)``, where *nbytes* is the total number of bytes of 1037 non-ancillary data written into the buffers, and *ancdata*, 1038 *msg_flags* and *address* are the same as for :meth:`recvmsg`. 1039 1040 Example:: 1041 1042 >>> import socket 1043 >>> s1, s2 = socket.socketpair() 1044 >>> b1 = bytearray(b'----') 1045 >>> b2 = bytearray(b'0123456789') 1046 >>> b3 = bytearray(b'--------------') 1047 >>> s1.send(b'Mary had a little lamb') 1048 22 1049 >>> s2.recvmsg_into([b1, memoryview(b2)[2:9], b3]) 1050 (22, [], 0, None) 1051 >>> [b1, b2, b3] 1052 [bytearray(b'Mary'), bytearray(b'01 had a 9'), bytearray(b'little lamb---')] 1053 1054 Availability: most Unix platforms, possibly others. 1055 1056 .. versionadded:: 3.3 1057 1058 1059.. method:: socket.recvfrom_into(buffer[, nbytes[, flags]]) 1060 1061 Receive data from the socket, writing it into *buffer* instead of creating a 1062 new bytestring. The return value is a pair ``(nbytes, address)`` where *nbytes* is 1063 the number of bytes received and *address* is the address of the socket sending 1064 the data. See the Unix manual page :manpage:`recv(2)` for the meaning of the 1065 optional argument *flags*; it defaults to zero. (The format of *address* 1066 depends on the address family --- see above.) 1067 1068 1069.. method:: socket.recv_into(buffer[, nbytes[, flags]]) 1070 1071 Receive up to *nbytes* bytes from the socket, storing the data into a buffer 1072 rather than creating a new bytestring. If *nbytes* is not specified (or 0), 1073 receive up to the size available in the given buffer. Returns the number of 1074 bytes received. See the Unix manual page :manpage:`recv(2)` for the meaning 1075 of the optional argument *flags*; it defaults to zero. 1076 1077 1078.. method:: socket.send(bytes[, flags]) 1079 1080 Send data to the socket. The socket must be connected to a remote socket. The 1081 optional *flags* argument has the same meaning as for :meth:`recv` above. 1082 Returns the number of bytes sent. Applications are responsible for checking that 1083 all data has been sent; if only some of the data was transmitted, the 1084 application needs to attempt delivery of the remaining data. For further 1085 information on this topic, consult the :ref:`socket-howto`. 1086 1087 1088.. method:: socket.sendall(bytes[, flags]) 1089 1090 Send data to the socket. The socket must be connected to a remote socket. The 1091 optional *flags* argument has the same meaning as for :meth:`recv` above. 1092 Unlike :meth:`send`, this method continues to send data from *bytes* until 1093 either all data has been sent or an error occurs. ``None`` is returned on 1094 success. On error, an exception is raised, and there is no way to determine how 1095 much data, if any, was successfully sent. 1096 1097 1098.. method:: socket.sendto(bytes, address) 1099 socket.sendto(bytes, flags, address) 1100 1101 Send data to the socket. The socket should not be connected to a remote socket, 1102 since the destination socket is specified by *address*. The optional *flags* 1103 argument has the same meaning as for :meth:`recv` above. Return the number of 1104 bytes sent. (The format of *address* depends on the address family --- see 1105 above.) 1106 1107 1108.. method:: socket.sendmsg(buffers[, ancdata[, flags[, address]]]) 1109 1110 Send normal and ancillary data to the socket, gathering the 1111 non-ancillary data from a series of buffers and concatenating it 1112 into a single message. The *buffers* argument specifies the 1113 non-ancillary data as an iterable of buffer-compatible objects 1114 (e.g. :class:`bytes` objects); the operating system may set a limit 1115 (:func:`~os.sysconf` value ``SC_IOV_MAX``) on the number of buffers 1116 that can be used. The *ancdata* argument specifies the ancillary 1117 data (control messages) as an iterable of zero or more tuples 1118 ``(cmsg_level, cmsg_type, cmsg_data)``, where *cmsg_level* and 1119 *cmsg_type* are integers specifying the protocol level and 1120 protocol-specific type respectively, and *cmsg_data* is a 1121 buffer-compatible object holding the associated data. Note that 1122 some systems (in particular, systems without :func:`CMSG_SPACE`) 1123 might support sending only one control message per call. The 1124 *flags* argument defaults to 0 and has the same meaning as for 1125 :meth:`send`. If *address* is supplied and not ``None``, it sets a 1126 destination address for the message. The return value is the 1127 number of bytes of non-ancillary data sent. 1128 1129 The following function sends the list of file descriptors *fds* 1130 over an :const:`AF_UNIX` socket, on systems which support the 1131 :const:`SCM_RIGHTS` mechanism. See also :meth:`recvmsg`. :: 1132 1133 import socket, array 1134 1135 def send_fds(sock, msg, fds): 1136 return sock.sendmsg([msg], [(socket.SOL_SOCKET, socket.SCM_RIGHTS, array.array("i", fds))]) 1137 1138 Availability: most Unix platforms, possibly others. 1139 1140 .. versionadded:: 3.3 1141 1142 1143.. method:: socket.set_inheritable(inheritable) 1144 1145 Set the :ref:`inheritable flag <fd_inheritance>` of the socket's file 1146 descriptor or socket's handle. 1147 1148 .. versionadded:: 3.4 1149 1150 1151.. method:: socket.setblocking(flag) 1152 1153 Set blocking or non-blocking mode of the socket: if *flag* is false, the 1154 socket is set to non-blocking, else to blocking mode. 1155 1156 This method is a shorthand for certain :meth:`~socket.settimeout` calls: 1157 1158 * ``sock.setblocking(True)`` is equivalent to ``sock.settimeout(None)`` 1159 1160 * ``sock.setblocking(False)`` is equivalent to ``sock.settimeout(0.0)`` 1161 1162 1163.. method:: socket.settimeout(value) 1164 1165 Set a timeout on blocking socket operations. The *value* argument can be a 1166 nonnegative floating point number expressing seconds, or ``None``. 1167 If a non-zero value is given, subsequent socket operations will raise a 1168 :exc:`timeout` exception if the timeout period *value* has elapsed before 1169 the operation has completed. If zero is given, the socket is put in 1170 non-blocking mode. If ``None`` is given, the socket is put in blocking mode. 1171 1172 For further information, please consult the :ref:`notes on socket timeouts <socket-timeouts>`. 1173 1174 1175.. method:: socket.setsockopt(level, optname, value) 1176 1177 .. index:: module: struct 1178 1179 Set the value of the given socket option (see the Unix manual page 1180 :manpage:`setsockopt(2)`). The needed symbolic constants are defined in the 1181 :mod:`socket` module (:const:`SO_\*` etc.). The value can be an integer or a 1182 bytes object representing a buffer. In the latter case it is up to the caller to 1183 ensure that the bytestring contains the proper bits (see the optional built-in 1184 module :mod:`struct` for a way to encode C structures as bytestrings). 1185 1186 1187.. method:: socket.shutdown(how) 1188 1189 Shut down one or both halves of the connection. If *how* is :const:`SHUT_RD`, 1190 further receives are disallowed. If *how* is :const:`SHUT_WR`, further sends 1191 are disallowed. If *how* is :const:`SHUT_RDWR`, further sends and receives are 1192 disallowed. 1193 1194 1195.. method:: socket.share(process_id) 1196 1197 Duplicate a socket and prepare it for sharing with a target process. The 1198 target process must be provided with *process_id*. The resulting bytes object 1199 can then be passed to the target process using some form of interprocess 1200 communication and the socket can be recreated there using :func:`fromshare`. 1201 Once this method has been called, it is safe to close the socket since 1202 the operating system has already duplicated it for the target process. 1203 1204 Availability: Windows. 1205 1206 .. versionadded:: 3.3 1207 1208 1209Note that there are no methods :meth:`read` or :meth:`write`; use 1210:meth:`~socket.recv` and :meth:`~socket.send` without *flags* argument instead. 1211 1212Socket objects also have these (read-only) attributes that correspond to the 1213values given to the :class:`socket` constructor. 1214 1215 1216.. attribute:: socket.family 1217 1218 The socket family. 1219 1220 1221.. attribute:: socket.type 1222 1223 The socket type. 1224 1225 1226.. attribute:: socket.proto 1227 1228 The socket protocol. 1229 1230 1231 1232.. _socket-timeouts: 1233 1234Notes on socket timeouts 1235------------------------ 1236 1237A socket object can be in one of three modes: blocking, non-blocking, or 1238timeout. Sockets are by default always created in blocking mode, but this 1239can be changed by calling :func:`setdefaulttimeout`. 1240 1241* In *blocking mode*, operations block until complete or the system returns 1242 an error (such as connection timed out). 1243 1244* In *non-blocking mode*, operations fail (with an error that is unfortunately 1245 system-dependent) if they cannot be completed immediately: functions from the 1246 :mod:`select` can be used to know when and whether a socket is available for 1247 reading or writing. 1248 1249* In *timeout mode*, operations fail if they cannot be completed within the 1250 timeout specified for the socket (they raise a :exc:`timeout` exception) 1251 or if the system returns an error. 1252 1253.. note:: 1254 At the operating system level, sockets in *timeout mode* are internally set 1255 in non-blocking mode. Also, the blocking and timeout modes are shared between 1256 file descriptors and socket objects that refer to the same network endpoint. 1257 This implementation detail can have visible consequences if e.g. you decide 1258 to use the :meth:`~socket.fileno()` of a socket. 1259 1260Timeouts and the ``connect`` method 1261^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 1262 1263The :meth:`~socket.connect` operation is also subject to the timeout 1264setting, and in general it is recommended to call :meth:`~socket.settimeout` 1265before calling :meth:`~socket.connect` or pass a timeout parameter to 1266:meth:`create_connection`. However, the system network stack may also 1267return a connection timeout error of its own regardless of any Python socket 1268timeout setting. 1269 1270Timeouts and the ``accept`` method 1271^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 1272 1273If :func:`getdefaulttimeout` is not :const:`None`, sockets returned by 1274the :meth:`~socket.accept` method inherit that timeout. Otherwise, the 1275behaviour depends on settings of the listening socket: 1276 1277* if the listening …
Large files files are truncated, but you can click here to view the full file