PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

SOCKETPAIR(3P)            POSIX Programmer's Manual           SOCKETPAIR(3P)

PROLOG         top

       This manual page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the
       corresponding Linux manual page for details of Linux behavior), or
       the interface may not be implemented on Linux.

NAME         top

       socketpair — create a pair of connected sockets

SYNOPSIS         top

       #include <sys/socket.h>

       int socketpair(int domain, int type, int protocol,
           int socket_vector[2]);

DESCRIPTION         top

       The socketpair() function shall create an unbound pair of connected
       sockets in a specified domain, of a specified type, under the
       protocol optionally specified by the protocol argument. The two
       sockets shall be identical. The file descriptors used in referencing
       the created sockets shall be returned in socket_vector[0] and
       socket_vector[1].

       The socketpair() function takes the following arguments:

       domain      Specifies the communications domain in which the sockets
                   are to be created.

       type        Specifies the type of sockets to be created.

       protocol    Specifies a particular protocol to be used with the
                   sockets.  Specifying a protocol of 0 causes socketpair()
                   to use an unspecified default protocol appropriate for
                   the requested socket type.

       socket_vector
                   Specifies a 2-integer array to hold the file descriptors
                   of the created socket pair.

       The type argument specifies the socket type, which determines the
       semantics of communications over the socket. The following socket
       types are defined; implementations may specify additional socket
       types:

       SOCK_STREAM   Provides sequenced, reliable, bidirectional,
                     connection-mode byte streams, and may provide a
                     transmission mechanism for out-of-band data.

       SOCK_DGRAM    Provides datagrams, which are connectionless-mode,
                     unreliable messages of fixed maximum length.

       SOCK_SEQPACKET
                     Provides sequenced, reliable, bidirectional,
                     connection-mode transmission paths for records. A
                     record can be sent using one or more output operations
                     and received using one or more input operations, but a
                     single operation never transfers part of more than one
                     record. Record boundaries are visible to the receiver
                     via the MSG_EOR flag.

       If the protocol argument is non-zero, it shall specify a protocol
       that is supported by the address family. If the protocol argument is
       zero, the default protocol for this address family and type shall be
       used. The protocols supported by the system are implementation-
       defined.

       The process may need to have appropriate privileges to use the
       socketpair() function or to create some sockets.

RETURN VALUE         top

       Upon successful completion, this function shall return 0; otherwise,
       −1 shall be returned and errno set to indicate the error.

ERRORS         top

       The socketpair() function shall fail if:

       EAFNOSUPPORT
              The implementation does not support the specified address
              family.

       EMFILE All, or all but one, of the file descriptors available to the
              process are currently open.

       ENFILE No more file descriptors are available for the system.

       EOPNOTSUPP
              The specified protocol does not permit creation of socket
              pairs.

       EPROTONOSUPPORT
              The protocol is not supported by the address family, or the
              protocol is not supported by the implementation.

       EPROTOTYPE
              The socket type is not supported by the protocol.

       The socketpair() function may fail if:

       EACCES The process does not have appropriate privileges.

       ENOBUFS
              Insufficient resources were available in the system to perform
              the operation.

       ENOMEM Insufficient memory was available to fulfill the request.

       The following sections are informative.

EXAMPLES         top

       None.

APPLICATION USAGE         top

       The documentation for specific address families specifies which
       protocols each address family supports. The documentation for
       specific protocols specifies which socket types each protocol
       supports.

       The socketpair() function is used primarily with UNIX domain sockets
       and need not be supported for other domains.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       socket(3p)

       The Base Definitions volume of POSIX.1‐2008, sys_socket.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                      SOCKETPAIR(3P)

Pages that refer to this page: sys_socket.h(0p)sys_un.h(0p)socket(3p)