unsigned int OEAtomGetSmallestRingSize(const OEAtomBase &atm)
Determine the size of the smallest ring that an atom is in. The
function OEFindRingAtomsAndBonds
should have been called before
calling this function. If the atom is not in a ring, i.e.
OEAtomBase::IsInRing
returns false, the value zero is
returned.