(a) Except as otherwise provided in subsection (b) of this Section, “dwelling” means a building or portion thereof, a tent, a vehicle, or other enclosed space which is used or intended for use as a human habitation, home or residence.
     (b) For the purposes of Section 19-3 of this Code, “dwelling” means a house, apartment, mobile home, trailer, or other living quarters in which at the time of the alleged offense the owners or occupants actually reside or in their absence intend within a reasonable period of time to reside.