You are viewing the version of this documentation from Perl blead. This is the main development branch of Perl. (git commit 1b72dea75a56a45f87c85e5ddd5e98dabaa6e272)
IO::Handle->format_formfeed(EXPR)
$FORMAT_FORMFEED
$^L

What formats output as a form feed. The default is \f.

You cannot call format_formfeed() on a handle, only as a static method. See IO::Handle.