phpman > perldoc > socket(2)

    socket SOCKET,DOMAIN,TYPE,PROTOCOL
            Opens a socket of the specified kind and attaches it to
            filehandle SOCKET. DOMAIN, TYPE, and PROTOCOL are specified the
            same as for the syscall of the same name. You should "use
            Socket" first to get the proper definitions imported. See the
            examples in "Sockets: Client/Server Communication" in perlipc.

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