Because any process can end any other process for which it has a process identifier, applications might lose information if a process ends the application before it can save its work. To prevent this loss of data, you can create a list of functions to clean up data and files before OS/2 ends the process. This list is called an exit list. OS/2 maintains an exit list for each process and calls these functions whenever the application is ended, whether by another process or by itself.
You call DosExitList to add to the exit list a routine that is to be given control when a process is ended (or finishes its execution). Multiple routines can be added to the list. When the process is ending, OS/2 transfers control to each address on the list.
Exit-list functions perform clean-up operations on resources. For example, an exit-list function can be used in a dynamic link library module to free resources or clear flags and semaphores when a client program has ended.