After all the calls from your application to the ILOG CPLEX Callable Library are complete, you must release the ILOG CPLEX environment by calling the routine CPXcloseCPLEX(). This routine tells ILOG CPLEX that:

• all application calls to the Callable Library are complete;
• ILOG CPLEX should release any memory allocated by ILOG CPLEX for this environment;
• the application has relinquished the ILOG CPLEX license for this run, thus making the license available to the next user.