socketpair(2)

1socketpair(2)                 System Calls Manual                socketpair(2)
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NAME

6       socketpair - create a pair of connected sockets
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LIBRARY

9       Standard C library (libc, -lc)
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SYNOPSIS

12       #include <sys/socket.h>
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14       int socketpair(int domain, int type, int protocol, int sv[2]);
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DESCRIPTION

17       The  socketpair()  call creates an unnamed pair of connected sockets in
18       the specified domain, of the specified type, and using  the  optionally
19       specified  protocol.   For  further  details  of  these  arguments, see
20       socket(2).
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22       The file descriptors used in referencing the new sockets  are  returned
23       in sv[0] and sv[1].  The two sockets are indistinguishable.
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RETURN VALUE

26       On  success,  zero is returned.  On error, -1 is returned, errno is set
27       to indicate the error, and sv is left unchanged
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29       On Linux (and other systems), socketpair() does not modify sv on  fail‐
30       ure.    A   requirement   standardizing  this  behavior  was  added  in
31       POSIX.1-2008 TC2.
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ERRORS

34       EAFNOSUPPORT
35              The specified address family is not supported on this machine.
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37       EFAULT The address sv does not specify a valid part of the process  ad‐
38              dress space.
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40       EMFILE The per-process limit on the number of open file descriptors has
41              been reached.
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43       ENFILE The system-wide limit on the total number of open files has been
44              reached.
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46       EOPNOTSUPP
47              The  specified  protocol  does  not  support  creation of socket
48              pairs.
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50       EPROTONOSUPPORT
51              The specified protocol is not supported on this machine.
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VERSIONS

54       On Linux, the only supported domains for this call are AF_UNIX (or syn‐
55       onymously, AF_LOCAL) and AF_TIPC (since Linux 4.12).
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STANDARDS

58       POSIX.1-2008.
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HISTORY

61       POSIX.1-2001, 4.4BSD.
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63       socketpair()  first  appeared  in  4.2BSD.   It  is  generally portable
64       to/from non-BSD systems supporting clones of the BSD socket layer  (in‐
65       cluding System V variants).
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67       Since   Linux  2.6.27,  socketpair()  supports  the  SOCK_NONBLOCK  and
68       SOCK_CLOEXEC flags in the type argument, as described in socket(2).
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