socketpair(2) - Linux manual page (original) (raw)

socketpair(2) System Calls Manual socketpair(2)

NAME top

   socketpair - create a pair of connected sockets

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <sys/socket.h>**

   **int socketpair(int** _domain_**, int** _type_**, int** _protocol_**, int** _sv_**[2]);**

DESCRIPTION top

   The **socketpair**() call creates an unnamed pair of connected sockets
   in the specified _domain_, of the specified _type_, and using the
   optionally specified _protocol_.  For further details of these
   arguments, see [socket(2)](../man2/socket.2.html).

   The file descriptors used in referencing the new sockets are
   returned in _sv[0]_ and _sv[1]_.  The two sockets are
   indistinguishable.

RETURN VALUE top

   On success, zero is returned.  On error, -1 is returned, _[errno](../man3/errno.3.html)_ is
   set to indicate the error, and _sv_ is left unchanged

   On Linux (and other systems), **socketpair**() does not modify _sv_ on
   failure.  A requirement standardizing this behavior was added in
   POSIX.1-2008 TC2.

ERRORS top

   **EAFNOSUPPORT**
          The specified address family is not supported on this
          machine.

   **EFAULT** The address _sv_ does not specify a valid part of the process
          address space.

   **EMFILE** The per-process limit on the number of open file
          descriptors has been reached.

   **ENFILE** The system-wide limit on the total number of open files has
          been reached.

   **EOPNOTSUPP**
          The specified protocol does not support creation of socket
          pairs.

   **EPROTONOSUPPORT**
          The specified protocol is not supported on this machine.

VERSIONS top

   On Linux, the only supported domains for this call are **AF_UNIX** (or
   synonymously, **AF_LOCAL**) and **AF_TIPC** (since Linux 4.12).

STANDARDS top

   POSIX.1-2008.

HISTORY top

   POSIX.1-2001, 4.4BSD.

   **socketpair**() first appeared in 4.2BSD.  It is generally portable
   to/from non-BSD systems supporting clones of the BSD socket layer
   (including System V variants).

   Since Linux 2.6.27, **socketpair**() supports the **SOCK_NONBLOCK** and
   **SOCK_CLOEXEC** flags in the _type_ argument, as described in
   [socket(2)](../man2/socket.2.html).

SEE ALSO top

   [pipe(2)](../man2/pipe.2.html), [read(2)](../man2/read.2.html), [socket(2)](../man2/socket.2.html), [write(2)](../man2/write.2.html), [socket(7)](../man7/socket.7.html), [unix(7)](../man7/unix.7.html)

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Linux man-pages 6.10 2024-07-23 socketpair(2)

Pages that refer to this page:pipe(2), socket(2), socketcall(2), syscalls(2), sockaddr(3type), fifo(7), pipe(7), signal-safety(7), socket(7), unix(7)