1SOCKETPAIR(3P) POSIX Programmer's Manual SOCKETPAIR(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
13 socketpair — create a pair of connected sockets
14
16 #include <sys/socket.h>
17 int socketpair(int domain, int type, int protocol,
19 int socket_vector[2]);
20
22 The socketpair() function shall create an unbound pair of connected
23 sockets in a specified domain, of a specified type, under the protocol
24 optionally specified by the protocol argument. The two sockets shall be
25 identical. The file descriptors used in referencing the created sockets
26 shall be returned in socket_vector[0] and socket_vector[1].
27 The socketpair() function takes the following arguments:
29 domain Specifies the communications domain in which the sockets
31 are to be created.
32 type Specifies the type of sockets to be created.
34 protocol Specifies a particular protocol to be used with the sock‐
36 ets. Specifying a protocol of 0 causes socketpair() to use
37 an unspecified default protocol appropriate for the
38 requested socket type.
39 socket_vector
41 Specifies a 2-integer array to hold the file descriptors of
42 the created socket pair.
43 The type argument specifies the socket type, which determines the
45 semantics of communications over the socket. The following socket types
46 are defined; implementations may specify additional socket types:
47 SOCK_STREAM Provides sequenced, reliable, bidirectional, connection-
49 mode byte streams, and may provide a transmission mecha‐
50 nism for out-of-band data.
51 SOCK_DGRAM Provides datagrams, which are connectionless-mode, unre‐
53 liable messages of fixed maximum length.
54 SOCK_SEQPACKET
56 Provides sequenced, reliable, bidirectional, connection-
57 mode transmission paths for records. A record can be sent
58 using one or more output operations and received using
59 one or more input operations, but a single operation
60 never transfers part of more than one record. Record
61 boundaries are visible to the receiver via the MSG_EOR
62 flag.
63 If the protocol argument is non-zero, it shall specify a protocol that
65 is supported by the address family. If the protocol argument is zero,
66 the default protocol for this address family and type shall be used.
67 The protocols supported by the system are implementation-defined.
68 The process may need to have appropriate privileges to use the socket‐
70 pair() function or to create some sockets.
71
73 Upon successful completion, this function shall return 0; otherwise, −1
74 shall be returned and errno set to indicate the error.
75
77 The socketpair() function shall fail if:
78 EAFNOSUPPORT
80 The implementation does not support the specified address fam‐
81 ily.
82 EMFILE All, or all but one, of the file descriptors available to the
84 process are currently open.
85 ENFILE No more file descriptors are available for the system.
87 EOPNOTSUPP
89 The specified protocol does not permit creation of socket pairs.
90 EPROTONOSUPPORT
92 The protocol is not supported by the address family, or the pro‐
93 tocol is not supported by the implementation.
94 EPROTOTYPE
96 The socket type is not supported by the protocol.
97 The socketpair() function may fail if:
99 EACCES The process does not have appropriate privileges.
101 ENOBUFS
103 Insufficient resources were available in the system to perform
104 the operation.
105 ENOMEM Insufficient memory was available to fulfill the request.
107 The following sections are informative.
109
111 None.
112
114 The documentation for specific address families specifies which proto‐
115 cols each address family supports. The documentation for specific pro‐
116 tocols specifies which socket types each protocol supports.
117 The socketpair() function is used primarily with UNIX domain sockets
119 and need not be supported for other domains.
120
122 None.
123
125 None.
126
128 socket()
129 The Base Definitions volume of POSIX.1‐2008, <sys_socket.h>
131
133 Portions of this text are reprinted and reproduced in electronic form
134 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
135 -- Portable Operating System Interface (POSIX), The Open Group Base
136 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
137 cal and Electronics Engineers, Inc and The Open Group. (This is
138 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
139 event of any discrepancy between this version and the original IEEE and
140 The Open Group Standard, the original IEEE and The Open Group Standard
141 is the referee document. The original Standard can be obtained online
142 at http://www.unix.org/online.html .
143 Any typographical or formatting errors that appear in this page are
145 most likely to have been introduced during the conversion of the source
146 files to man page format. To report such errors, see https://www.ker‐
147 nel.org/doc/man-pages/reporting_bugs.html .
148IEEE/The Open Group 2013 SOCKETPAIR(3P)