When to Invoke ILF Routines: Event Points
One important consideration when developing an ILF routine is to designate the exact point during the process when the routine will execute. You control the timing of when ILF routines execute by using appropriate event points. An event point is a predefined chronological point during the execution of a process when an ILF routine can be executed.
There are several different types of processes (menus, inputs, etc.) and several process components (frames, images, etc.). Each process component has its own specific set of event points. You can develop and execute an ILF routine at any one of these predefined event points, depending on the unique requirements of your application.
As an example, any process that invokes a child process has both a Pre-Invocation and a Post Invocation event point. You can select either of these event points (as options when you are defining a child invocation) and develop an ILF routine. A pre-invocation ILF routine executes immediately before the child process is invoked, while a post invocation ILF routine executes immediately after the child process completes.
You may want the application to test certain conditions and, based upon the results, perform a specified set of actions at a precise point or points in time. It is the event points that accommodate this requirement to control the timing of executing an ILF routine.
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