return the filehandles for input and output or <A HREF="../../lib/Pod/perlfunc.html#item_undef"><CODE>undef</CODE></A> if <A HREF="#item_readline"><CODE>readline</CODE></A>
Returns a reference to a hash with keys being features present in
current implementation. Several optional features are used in the
minimal interface: <CODE>appname</CODE> should be present if the first argument
to <A HREF="#item_new"><CODE>new</CODE></A> is recognized, and <CODE>minline</CODE> should be present if
<A HREF="#item_MinLine"><CODE>MinLine</CODE></A> method is not dummy. <CODE>autohistory</CODE> should be present if
lines are put into history automatically (maybe subject to
<A HREF="#item_MinLine"><CODE>MinLine</CODE></A>), and <A HREF="#item_addhistory"><CODE>addhistory</CODE></A> if <A HREF="#item_addhistory"><CODE>addhistory</CODE></A> method is not dummy.
<P>If <A HREF="#item_Features"><CODE>Features</CODE></A> method reports a feature <CODE>attribs</CODE> as present, the
method <A HREF="#item_Attribs"><CODE>Attribs</CODE></A> is not dummy.</P>