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Diffstat (limited to 'man2/socket.2')
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diff --git a/man2/socket.2 b/man2/socket.2 deleted file mode 100644 index b83bd5b..0000000 --- a/man2/socket.2 +++ /dev/null @@ -1,493 +0,0 @@ -'\" t -.\" Copyright (c) 1983, 1991 The Regents of the University of California. -.\" All rights reserved. -.\" -.\" SPDX-License-Identifier: BSD-4-Clause-UC -.\" -.\" $Id: socket.2,v 1.4 1999/05/13 11:33:42 freitag Exp $ -.\" -.\" Modified 1993-07-24 by Rik Faith <faith@cs.unc.edu> -.\" Modified 1996-10-22 by Eric S. Raymond <esr@thyrsus.com> -.\" Modified 1998, 1999 by Andi Kleen <ak@muc.de> -.\" Modified 2002-07-17 by Michael Kerrisk <mtk.manpages@gmail.com> -.\" Modified 2004-06-17 by Michael Kerrisk <mtk.manpages@gmail.com> -.\" -.TH socket 2 2024-01-28 "Linux man-pages 6.7" -.SH NAME -socket \- create an endpoint for communication -.SH LIBRARY -Standard C library -.RI ( libc ", " \-lc ) -.SH SYNOPSIS -.nf -.B #include <sys/socket.h> -.P -.BI "int socket(int " domain ", int " type ", int " protocol ); -.fi -.SH DESCRIPTION -.BR socket () -creates an endpoint for communication and returns a file descriptor -that refers to that endpoint. -The file descriptor returned by a successful call will be -the lowest-numbered file descriptor not currently open for the process. -.P -The -.I domain -argument specifies a communication domain; this selects the protocol -family which will be used for communication. -These families are defined in -.IR <sys/socket.h> . -The formats currently understood by the Linux kernel include: -.TS -tab(:); -l1 lw40 l. -Name:Purpose:Man page -T{ -.B AF_UNIX -T}:T{ -Local communication -T}:T{ -.BR unix (7) -T} -T{ -.B AF_LOCAL -T}:T{ -Synonym for -.B AF_UNIX -T}:T{ -T} -T{ -.B AF_INET -T}:IPv4 Internet protocols:T{ -.BR ip (7) -T} -T{ -.B AF_AX25 -T}:T{ -Amateur radio AX.25 protocol -T}:T{ -.\" Part of ax25-tools -.BR ax25 (4) -T} -T{ -.B AF_IPX -T}:IPX \- Novell protocols: -T{ -.B AF_APPLETALK -T}:AppleTalk:T{ -.BR ddp (7) -T} -T{ -.B AF_X25 -T}:ITU-T X.25 / ISO/IEC\~8208 protocol:T{ -.BR x25 (7) -T} -T{ -.B AF_INET6 -T}:IPv6 Internet protocols:T{ -.BR ipv6 (7) -T} -T{ -.B AF_DECnet -T}:T{ -DECet protocol sockets -T} -T{ -.B AF_KEY -T}:T{ -Key management protocol, originally developed for usage with IPsec -T} -T{ -.B AF_NETLINK -T}:T{ -Kernel user interface device -T}:T{ -.BR netlink (7) -T} -T{ -.B AF_PACKET -T}:T{ -Low-level packet interface -T}:T{ -.BR packet (7) -T} -T{ -.B AF_RDS -T}:T{ -.\" commit: 639b321b4d8f4e412bfbb2a4a19bfebc1e68ace4 -Reliable Datagram Sockets (RDS) protocol -T}:T{ -.\" rds-tools: https://github.com/oracle/rds-tools/blob/master/rds.7 -.\" rds-tools: https://github.com/oracle/rds-tools/blob/master/rds-rdma.7 -.BR rds (7) -.br -.BR rds\-rdma (7) -T} -T{ -.B AF_PPPOX -T}:T{ -Generic PPP transport layer, for setting up L2 tunnels -(L2TP and PPPoE) -T} -T{ -.B AF_LLC -T}:T{ -.\" linux-history commit: 34beb106cde7da233d4df35dd3d6cf4fee937caa -Logical link control (IEEE 802.2 LLC) protocol -T} -T{ -.B AF_IB -T}:T{ -.\" commits: 8d36eb01da5d371f..ce117ffac2e93334 -InfiniBand native addressing -T} -T{ -.B AF_MPLS -T}:T{ -.\" commits: 0189197f441602acdca3f97750d392a895b778fd -Multiprotocol Label Switching -T} -T{ -.B AF_CAN -T}:T{ -.\" commits: 8dbde28d9711475a..5423dd67bd0108a1 -Controller Area Network automotive bus protocol -T} -T{ -.B AF_TIPC -T}:T{ -.\" commits: b97bf3fd8f6a16966d4f18983b2c40993ff937d4 -TIPC, "cluster domain sockets" protocol -T} -T{ -.B AF_BLUETOOTH -T}:T{ -.\" commits: 8d36eb01da5d371f..ce117ffac2e93334 -Bluetooth low-level socket protocol -T} -T{ -.B AF_ALG -T}:T{ -.\" commit: 03c8efc1ffeb6b82a22c1af8dd908af349563314 -Interface to kernel crypto API -T} -T{ -.B AF_VSOCK -T}:T{ -.\" commit: d021c344051af91f42c5ba9fdedc176740cbd238 -VSOCK (originally "VMWare VSockets") protocol -for hypervisor-guest communication -T}:T{ -.BR vsock (7) -T} -T{ -.B AF_KCM -T}:T{ -.\" commit: 03c8efc1ffeb6b82a22c1af8dd908af349563314 -KCM (kernel connection multiplexer) interface -T} -T{ -.B AF_XDP -T}:T{ -.\" commit: c0c77d8fb787cfe0c3fca689c2a30d1dad4eaba7 -XDP (express data path) interface -T} -.TE -.P -Further details of the above address families, -as well as information on several other address families, can be found in -.BR address_families (7). -.P -The socket has the indicated -.IR type , -which specifies the communication semantics. -Currently defined types -are: -.TP 16 -.B SOCK_STREAM -Provides sequenced, reliable, two-way, connection-based byte streams. -An out-of-band data transmission mechanism may be supported. -.TP -.B SOCK_DGRAM -Supports datagrams (connectionless, unreliable messages of a fixed -maximum length). -.TP -.B SOCK_SEQPACKET -Provides a sequenced, reliable, two-way connection-based data -transmission path for datagrams of fixed maximum length; a consumer is -required to read an entire packet with each input system call. -.TP -.B SOCK_RAW -Provides raw network protocol access. -.TP -.B SOCK_RDM -Provides a reliable datagram layer that does not guarantee ordering. -.TP -.B SOCK_PACKET -Obsolete and should not be used in new programs; -see -.BR packet (7). -.P -Some socket types may not be implemented by all protocol families. -.P -Since Linux 2.6.27, the -.I type -argument serves a second purpose: -in addition to specifying a socket type, -it may include the bitwise OR of any of the following values, -to modify the behavior of -.BR socket (): -.TP 16 -.B SOCK_NONBLOCK -Set the -.B O_NONBLOCK -file status flag on the open file description (see -.BR open (2)) -referred to by the new file descriptor. -Using this flag saves extra calls to -.BR fcntl (2) -to achieve the same result. -.TP -.B SOCK_CLOEXEC -Set the close-on-exec -.RB ( FD_CLOEXEC ) -flag on the new file descriptor. -See the description of the -.B O_CLOEXEC -flag in -.BR open (2) -for reasons why this may be useful. -.P -The -.I protocol -specifies a particular protocol to be used with the socket. -Normally only a single protocol exists to support a particular -socket type within a given protocol family, in which case -.I protocol -can be specified as 0. -However, it is possible that many protocols may exist, in -which case a particular protocol must be specified in this manner. -The protocol number to use is specific to the \*(lqcommunication domain\*(rq -in which communication is to take place; see -.BR protocols (5). -See -.BR getprotoent (3) -on how to map protocol name strings to protocol numbers. -.P -Sockets of type -.B SOCK_STREAM -are full-duplex byte streams. -They do not preserve -record boundaries. -A stream socket must be in -a -.I connected -state before any data may be sent or received on it. -A connection to -another socket is created with a -.BR connect (2) -call. -Once connected, data may be transferred using -.BR read (2) -and -.BR write (2) -calls or some variant of the -.BR send (2) -and -.BR recv (2) -calls. -When a session has been completed a -.BR close (2) -may be performed. -Out-of-band data may also be transmitted as described in -.BR send (2) -and received as described in -.BR recv (2). -.P -The communications protocols which implement a -.B SOCK_STREAM -ensure that data is not lost or duplicated. -If a piece of data for which -the peer protocol has buffer space cannot be successfully transmitted -within a reasonable length of time, then the connection is considered -to be dead. -When -.B SO_KEEPALIVE -is enabled on the socket the protocol checks in a protocol-specific -manner if the other end is still alive. -A -.B SIGPIPE -signal is raised if a process sends or receives -on a broken stream; this causes naive processes, -which do not handle the signal, to exit. -.B SOCK_SEQPACKET -sockets employ the same system calls as -.B SOCK_STREAM -sockets. -The only difference is that -.BR read (2) -calls will return only the amount of data requested, -and any data remaining in the arriving packet will be discarded. -Also all message boundaries in incoming datagrams are preserved. -.P -.B SOCK_DGRAM -and -.B SOCK_RAW -sockets allow sending of datagrams to correspondents named in -.BR sendto (2) -calls. -Datagrams are generally received with -.BR recvfrom (2), -which returns the next datagram along with the address of its sender. -.P -.B SOCK_PACKET -is an obsolete socket type to receive raw packets directly from the -device driver. -Use -.BR packet (7) -instead. -.P -An -.BR fcntl (2) -.B F_SETOWN -operation can be used to specify a process or process group to receive a -.B SIGURG -signal when the out-of-band data arrives or -.B SIGPIPE -signal when a -.B SOCK_STREAM -connection breaks unexpectedly. -This operation may also be used to set the process or process group -that receives the I/O and asynchronous notification of I/O events via -.BR SIGIO . -Using -.B F_SETOWN -is equivalent to an -.BR ioctl (2) -call with the -.B FIOSETOWN -or -.B SIOCSPGRP -argument. -.P -When the network signals an error condition to the protocol module (e.g., -using an ICMP message for IP) the pending error flag is set for the socket. -The next operation on this socket will return the error code of the pending -error. -For some protocols it is possible to enable a per-socket error queue -to retrieve detailed information about the error; see -.B IP_RECVERR -in -.BR ip (7). -.P -The operation of sockets is controlled by socket level -.IR options . -These options are defined in -.IR <sys/socket.h> . -The functions -.BR setsockopt (2) -and -.BR getsockopt (2) -are used to set and get options. -.SH RETURN VALUE -On success, a file descriptor for the new socket is returned. -On error, \-1 is returned, and -.I errno -is set to indicate the error. -.SH ERRORS -.TP -.B EACCES -Permission to create a socket of the specified type and/or protocol -is denied. -.TP -.B EAFNOSUPPORT -The implementation does not support the specified address family. -.TP -.B EINVAL -Unknown protocol, or protocol family not available. -.TP -.B EINVAL -.\" Since Linux 2.6.27 -Invalid flags in -.IR type . -.TP -.B EMFILE -The per-process limit on the number of open file descriptors has been reached. -.TP -.B ENFILE -The system-wide limit on the total number of open files has been reached. -.TP -.BR ENOBUFS " or " ENOMEM -Insufficient memory is available. -The socket cannot be -created until sufficient resources are freed. -.TP -.B EPROTONOSUPPORT -The protocol type or the specified protocol is not -supported within this domain. -.P -Other errors may be generated by the underlying protocol modules. -.SH STANDARDS -POSIX.1-2008. -.P -.B SOCK_NONBLOCK -and -.B SOCK_CLOEXEC -are Linux-specific. -.SH HISTORY -POSIX.1-2001, 4.4BSD. -.P -.BR socket () -appeared in 4.2BSD. -It is generally portable to/from -non-BSD systems supporting clones of the BSD socket layer (including -System\ V variants). -.P -The manifest constants used under 4.x BSD for protocol families -are -.BR PF_UNIX , -.BR PF_INET , -and so on, while -.BR AF_UNIX , -.BR AF_INET , -and so on are used for address -families. -However, already the BSD man page promises: "The protocol -family generally is the same as the address family", and subsequent -standards use AF_* everywhere. -.SH EXAMPLES -An example of the use of -.BR socket () -is shown in -.BR getaddrinfo (3). -.SH SEE ALSO -.BR accept (2), -.BR bind (2), -.BR close (2), -.BR connect (2), -.BR fcntl (2), -.BR getpeername (2), -.BR getsockname (2), -.BR getsockopt (2), -.BR ioctl (2), -.BR listen (2), -.BR read (2), -.BR recv (2), -.BR select (2), -.BR send (2), -.BR shutdown (2), -.BR socketpair (2), -.BR write (2), -.BR getprotoent (3), -.BR address_families (7), -.BR ip (7), -.BR socket (7), -.BR tcp (7), -.BR udp (7), -.BR unix (7) -.P -\[lq]An Introductory 4.3BSD Interprocess Communication Tutorial\[rq] -and -\[lq]BSD Interprocess Communication Tutorial\[rq], -reprinted in -.I UNIX Programmer's Supplementary Documents Volume 1. |