Must a barbarian in a whirling frenzy take a full attack to make the extra attack?

Question

The rage variant whirling frenzy says that

While in a whirling frenzy, the barbarian may make one extra attack in a round at his highest base attack bonus, but this attack takes a -2 penalty, as does each other attack made that round. (Unearthed Arcana 66)

This thread is inconclusive. Must the creature take the full attack action to make the extra attack granted by the rage variant whirling frenzy?

Answer 1

Yes; Whirling Frenzy does not list an exception to the general multiple-attack rule

I suppose, on some level, you have your extra attack even if you don’t full attack, but you cannot use it unless you full attack because of this rule:

_{Combat > Actions in Combat > Full-round Actions > Full Attack}

If you get more than one attack per round [...] for some special reason you must use a full-round action to get your additional attacks.

The only thing I am aware of that gets around this requirement in a general situation is Tome of Battle’s Snap Kick:

When you make a melee attack with one or more melee weapons (including a standard attack, full attack, or even a strike maneuver), you can make an additional attack at your highest attack bonus.

This parenthetical is necessary to get Snap Kick to have this behavior.