> Languages and APIs > The ILOG CPLEX Callable Library > ILOG CPLEX Programming Practices > Callbacks

The Callable Library supports callbacks so that you can define functions that will be called at crucial points in your application:

In addition, callback functions can call CPXgetcallbackinfo to retrieve information about the progress of an optimization algorithm. They can also return a value to indicate whether an optimization should be aborted. CPXgetcallbackinfo and certain other callback-specific routines are the only ones of the Callable Library that a user-defined callback may call. (Of course, calls to routines not in the Callable Library are permitted.)

Using Callbacks explores callback facilities in greater detail.