> Languages and APIs > The ILOG CPLEX Callable Library > ILOG CPLEX Programming Practices > Ownership of Problem Data

The ILOG CPLEX Callable Library does not take ownership of user memory. All arguments are copied from your user-defined arrays into ILOG CPLEX-allocated memory. ILOG CPLEX manages all problem-related memory. After you call a ILOG CPLEX routine that copies data into a ILOG CPLEX problem object, you can free or reuse the memory you allocated as arguments to the copying routine.