c# - Why call Dispose() before main() exits?

Question

My .net service cleans up all its unmanaged resources by calling resourceName.Dispose() in a finally block before the Main() loop exits.

Do I really have to do this?

Am I correct in thinking that I can’t leak any resources because the process is ending? Windows will close any handles that are no longer being used, right?

Answer 1

There is no limit to the types of resources that may be encapsulated by an object implementing IDisposable. The vast majority of resources encapsulated by IDisposable objects will be cleaned up by the operating system when a process shuts down, but some programs may use resources the operating system knows nothing about. For example, a database application which requires a locking pattern that isn't supported by the underlying database might use one or more tables to keep track of what things are "checked out" and by whom. A class which "checks out" resources using such tables could ensure in its Dispose method that everything gets checked back in, but if the program shuts down without the class having a chance to clean up the tables, the resources guarded by that table would be left dangling. Since the operating system would have no clue what any of those tables mean, it would have no way of cleaning them up.