bool OESetDistance(OEMolBase &mol, OEAtomBase *a, OEAtomBase *b, double dist)

Sets the distance between two atoms to the value specified by the argument dist. The two atoms must be bonded together. The atom passed in as b is displaced. If the bond defined by atoms is in a ring, no change to the distance will occur. The function returns true if it completes successfully. The function returns false if the atoms do not form a bond, if the bond is part of a ring, or if the atoms are on top of each other.

The molecule that the pair of atom belongs to.
The first atom.
The second atom.
The distance.