Gurobi constraint object. Constraints are always associated with a particular model. You create a constraint object by adding a constraint to a model (using GRBModel::addConstr), rather than by using a GRBConstr constructor.

The methods on constraint objects are used to get and set constraint attributes. For example, constraint right-hand sides can be queried by calling get( GRB_DoubleAttr_RHS). Note that you can also query attributes for a set of constraints at once. This is done using the attribute query method on the GRBModel object (GRBModel::get).