=over

=item sockatmark SOCKET

Returns true if the socket is positioned at the out-of-band mark
(also known as the urgent data mark), false otherwise.  Use right
after reading from the socket.

Not available directly, one has to import the function from
the IO::Socket extension

    use IO::Socket 'sockatmark';

Even this doesn't guarantee that sockatmark() really is available,
though, because sockatmark() is a relatively recent addition to
the family of socket functions.  If it is unavailable, attempt to
use it will fail

	IO::Socket::atmark not implemented on this architecture ...

See also L<IO::Socket>.

=back