Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. Why?

I need a full explantation for this concept.

Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid.

-
Why do you think so? A straight solenoid is clearly a limit of a very large thin torus, so if it were possible for any torus, it would be possible in the straight limit, too. If the currents are running strictly around the surface of the solenoid or torus, the field will be inside and strictly vanish outside. –  Luboš Motl Sep 23 '12 at 7:11
This is not from my thoughts. I found this piece from a book. But lost it somewhere. –  BigSack Sep 23 '12 at 7:17