CLR Memory Management & UnManaged Objects

Question

Dear All Please help me to sort one of my doubts regarding Release of Un-Managed Objects. If we are not explicitly calling dispose/close method for un-managed objects neither we are implementing finalizer for this unmanaged objects then what will happened for this unmanaged objects. Whether Operating system will take care after some time to release it or it will stay there till Operating system shouldn't get restarted. Please share your views regarding it. Regards Ashish Khandelwal

Sam Hobbs · Answer

There are some items that will never be freed until the system restarts. The problem has as far as I know been reduced in serisouness but as far as I know the problem still exists. You probably do not need to be concerned about that; there are managed classes for those things and you are not likely to need to develop your own unmanaged objects that could have the problem. The C++ compiler and most C++ programmers consider memory leaks to be a serious problem. Certainly it is unlikely that there will be any memory leaks after your application finishes but most C++ programmers would consider it to be sloppy to depend on that. It is a real problem for long-running programs and programs that make extensive use of resources that do not get freed. C# and the .Net libraries are designed to use garbage collection and make memory use easy. Unfortunately that is a problem for unmanaged code and for that C# can be confusing and frustrating. It is not a matter of our views; it is a matter of what the truth is. The truth is that there are no easy answers. You must spend time learning the subject if you need to develop software such as what you are asking about.

Vulpes · Answer

Any unmanaged resources which haven't been disposed of already will generally be reclaimed by the operating system when the managed process ends. In the case of kernel objects (mutexes semaphores etc) the process's handle to the kernel obejct will be closed when the process terminates though the objects themselves will continue to exist until all handles to them held by other processes have been closed. So generally speaking holding on to unmanaged resources which are no longer needed should only cause a memory leak whilst the managed process is still active.