socketpair

socketpair SOCKET1,SOCKET2,DOMAIN,TYPE,PROTOCOL

Creates an unnamed pair of sockets in the specified domain, of the specified type. DOMAIN, TYPE, and PROTOCOL are specified the same as for the syscall of the same name. If unimplemented, raises an exception. Returns true if successful.

On systems that support a close-on-exec flag on files, the flag will be set for the newly opened file descriptors, as determined by the value of $^F. See $^F in perlvar.

Some systems defined pipe in terms of socketpair, in which a call to pipe(Rdr, Wtr) is essentially:

use Socket;
socketpair(Rdr, Wtr, AF_UNIX, SOCK_STREAM, PF_UNSPEC);
shutdown(Rdr, 1);        # no more writing for reader
shutdown(Wtr, 0);        # no more reading for writer

See perlipc for an example of socketpair use. Perl 5.8 and later will emulate socketpair using IP sockets to localhost if your system implements sockets but not socketpair.

Portability issues: socketpair in perlport.