Note however, that the resulting archive will
only be able to be untarred with tar tools that support the chosen format.

<p>The default for the longfile
attribute is <code>warn</code> which behaves just like the gnu option except
that it produces a warning for each file path encountered that does not match
the limit.  It uses gnu rather than posix for backwards compatibility
  reasons.</p>

<p>To achivieve best interoperability you should use
  either <code>fail</code> or <code>posix</code> for the longfil