This function creates and returns a constraint (an instance of IloConstraint) for use in a model. When its parameters are two sets of variables, such as var2 and var3, the constraint forces the union of the sets var2 and var3 to be precisely the elements of the set unionSet. Likewise, when its parameters include an array of set variables, such as vars, the constraint forces the union of the elements of that array to be unionSet.

In order for the constraint to take effect, you must add it to a model with the template IloAdd or the member function IloModel::add and extract the model for an algorithm with the member function IloAlgorithm::extract.