=over

=item shutdown SOCKET,HOW
X<shutdown>

Shuts down a socket connection in the manner indicated by HOW, which
has the same interpretation as in the syscall of the same name.

    shutdown(SOCKET, 0);    # I/we have stopped reading data
    shutdown(SOCKET, 1);    # I/we have stopped writing data
    shutdown(SOCKET, 2);    # I/we have stopped using this socket

This is useful with sockets when you want to tell the other
side you're done writing but not done reading, or vice versa.
It's also a more insistent form of close because it also
disables the file descriptor in any forked copies in other
processes.

Returns C<1> for success; on error, returns C<undef> if
the first argument is not a valid filehandle, or returns C<0> and sets
C<$!> for any other failure.

=back