Calling cplex.solve returns a Boolean indicating whether or not a feasible solution (but not necessarily the optimal one) has been found. To obtain more of the information about the model that ILOG CPLEX found during the call to the solve method, cplex.getStatus can be called. It returns a member of the nested enumeration IloAlgorithm::Status . The fully qualified names of those symbols have the IloAlgorithm prefix. Table 1.6 shows what each return status means for the extracted model. Table 1.6 Algorithm Status and Information About the Model  Return Status Feasible Optimal Infeasible Unbounded InfeasibleOrUnbounded Unknown Error As can be seen, these statuses indicate information about the model that the ILOG CPLEX optimizer was able to prove during the last call to method solve . In addition, the ILOG CPLEX optimizer provides information about how it terminated. For example, it may have terminated with only a feasible but not optimal solution because it hit a limit or because a user callback terminated the optimization. Further information is accessible by calling solution query routines, such as method cplex.getCplexStatus , which returns a member of the nested enumeration type IloCplex::CplexStatus , or methods cplex.isPrimalFeasible or cplex.isDualFeasible . For more information about those status codes, see the ILOG CPLEX Ref erence Manual.