This function creates and returns a constraint (an instance of IloConstraint) for use in a model. The constraint forces var2 to the sum of the values returned by the function f when it is applied to the variable var1.

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.