SOCKETPAIR(2) Linux Programmer's Manual SOCKETPAIR(2)
socketpair - create a pair of connected sockets
#include <sys/types.h> /* See NOTES */
int socketpair(int domain, int type, int protocol, int sv);
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).
The descriptors used in referencing the new sockets are returned in sv and sv. The
two sockets are indistinguishable.
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.
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.
The specified protocol does not support creation of socket pairs.
The specified protocol is not supported on this machine.
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 Sys-
tem V variants).
On Linux, the only supported domain for this call is AF_UNIX (or synonymously, AF_LOCAL).
(Most implementations have the same restriction.)
Since Linux 2.6.27, socketpair() supports the SOCK_NONBLOCK and SOCK_CLOEXEC flags
described in socket(2).
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.
pipe(2), read(2), socket(2), write(2), socket(7), unix(7)
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Linux 2008-10-11 SOCKETPAIR(2)