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SOCKETPAIR(2) Linux Programmer's Manual SOCKETPAIR(2) NAME socketpair - create a pair of connected sockets SYNOPSIS #include <sys/types.h> /* See NOTES */ #include <sys/socket.h> int socketpair(int d, int type, int protocol, int sv[2]); DESCRIPTION The socketpair() call creates an unnamed pair of connected sockets in the specified domain d, of the specified type, and using the optionally specified protocol. The descriptors used in referencing the new sock- ets are returned in sv[0] and sv[1]. The two sockets are indistin- guishable. RETURN VALUE On success, zero is returned. On error, -1 is returned, and errno is set appropriately. ERRORS 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 Too many descriptors are in use by this process. ENFILE The system 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. CONFORMING TO 4.4BSD, POSIX.1-2001. The socketpair() function call appeared in 4.2BSD. It is generally portable to/from non-BSD systems supporting clones of the BSD socket layer (including System V variants). NOTES On Linux, the only supported domain for this call is AF_UNIX (or syn- onymously, AF_LOCAL). (Most implementations have the same restric- tion.) POSIX.1-2001 does not require the inclusion of <sys/types.h>, and this header file is not required on Linux. However, some historical (BSD) implementations required this header file, and portable applications are probably wise to include it. SEE ALSO pipe(2), read(2), socket(2), write(2), unix(7) Linux 2004-06-17 SOCKETPAIR(2)