1SOCKETPAIR(P) POSIX Programmer's Manual SOCKETPAIR(P)
2
6 socketpair - create a pair of connected sockets
7
9 #include <sys/socket.h>
10 int socketpair(int domain, int type, int protocol,
12 int socket_vector[2]);
13
16 The socketpair() function shall create an unbound pair of connected
17 sockets in a specified domain, of a specified type, under the protocol
18 optionally specified by the protocol argument. The two sockets shall be
19 identical. The file descriptors used in referencing the created sockets
20 shall be returned in socket_vector[0] and socket_vector[1].
21 The socketpair() function takes the following arguments:
23 domain Specifies the communications domain in which the sockets are to
25 be created.
26 type Specifies the type of sockets to be created.
28 protocol
30 Specifies a particular protocol to be used with the sockets.
31 Specifying a protocol of 0 causes socketpair() to use an unspec‐
32 ified default protocol appropriate for the requested socket
33 type.
34 socket_vector
36 Specifies a 2-integer array to hold the file descriptors of the
37 created socket pair.
38 The type argument specifies the socket type, which determines the
41 semantics of communications over the socket. The following socket types
42 are defined; implementations may specify additional socket types:
43 SOCK_STREAM
45 Provides sequenced, reliable, bidirectional, connection-mode
46 byte streams, and may provide a transmission mechanism for out-
47 of-band data.
48 SOCK_DGRAM
50 Provides datagrams, which are connectionless-mode, unreliable
51 messages of fixed maximum length.
52 SOCK_SEQPACKET
54 Provides sequenced, reliable, bidirectional, connection-mode
55 transmission paths for records. A record can be sent using one
56 or more output operations and received using one or more input
57 operations, but a single operation never transfers part of more
58 than one record. Record boundaries are visible to the receiver
59 via the MSG_EOR flag.
60 If the protocol argument is non-zero, it shall specify a protocol that
63 is supported by the address family. If the protocol argument is zero,
64 the default protocol for this address family and type shall be used.
65 The protocols supported by the system are implementation-defined.
66 The process may need to have appropriate privileges to use the socket‐
68 pair() function or to create some sockets.
69
71 Upon successful completion, this function shall return 0; otherwise, -1
72 shall be returned and errno set to indicate the error.
73
75 The socketpair() function shall fail if:
76 EAFNOSUPPORT
78 The implementation does not support the specified address fam‐
80 ily.
81 EMFILE No more file descriptors are available for this process.
83 ENFILE No more file descriptors are available for the system.
85 EOPNOTSUPP
87 The specified protocol does not permit creation of socket pairs.
88 EPROTONOSUPPORT
90 The protocol is not supported by the address family, or the pro‐
92 tocol is not supported by the implementation.
93 EPROTOTYPE
95 The socket type is not supported by the protocol.
96 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.
110
112 None.
113
115 The documentation for specific address families specifies which proto‐
116 cols each address family supports. The documentation for specific pro‐
117 tocols specifies which socket types each protocol supports.
118 The socketpair() function is used primarily with UNIX domain sockets
120 and need not be supported for other domains.
121
123 None.
124
126 None.
127
129 socket() , the Base Definitions volume of IEEE Std 1003.1-2001,
130 <sys/socket.h>
131
133 Portions of this text are reprinted and reproduced in electronic form
134 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
135 -- Portable Operating System Interface (POSIX), The Open Group Base
136 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
137 Electrical and Electronics Engineers, Inc and The Open Group. In the
138 event of any discrepancy between this version and the original IEEE and
139 The Open Group Standard, the original IEEE and The Open Group Standard
140 is the referee document. The original Standard can be obtained online
141 at http://www.opengroup.org/unix/online.html .
142IEEE/The Open Group 2003 SOCKETPAIR(P)