What happens to a process handle once the process was ended?

Question

if I have a handle to some windows process which has stopped (killed or just ended):

1. Will the handle (or better the memory behind it) be re-used for another process?
2. Or will GetExitCodeProcess() for example get the correct result forever from now on?

If 1. is true: How "long" would GetExitCodeProcess() work?
If 2. is true: Wouldn't that mean that I can bring down the OS with starting/killing new processes, since I create more and more handles (and the OS reserves memory for them)?

I'm a bit confused about the concept of handles.

Thank you in advance!

Answer 1

The handle indirectly points to an kernel object. As long as there are open handles, the object will be kept alive.

Will the handle (or better the memory behind it) be re-used for another process?

The numeric value of the handle (or however it is implemented) might get reused, but that doesn't mean it'll always point to the same thing. Just like process IDs.

Or will GetExitCodeProcess() for example get the correct result forever from now on?

No. When all handles to the process are closed, the process object is freed (along with its exit code). Note that running process holds an implicit handle to itself. You can hold an open handle, though, as long as you need it.

If 2. is true: Wouldn't that mean that I can bring down the OS with starting/killing new processes, since I create more and more handles (and the OS reserves memory for them)?

There are many ways to starve the system. It will either start heavily swapping or just fail to spawn a new process at some point.

Answer 2

Short answer:

GetExitCodeProcess works until you call CloseHandle, after what the process object will be released and may be reused.

Long answer: See Cat Plus Plus's answer.