Is processes threads (or whole process) suspended

Question

I would like to check if the processes' threads (the whole process) are suspended. I'm obtaining each process thread by this code:

var threads = Proc.Threads;
for (int x = 0; x < threads.Count; x++) {
var thread = threads[x];

However System.Diagnostics.ThreadState doesn't contain Suspended, but System.Threading.ThreadState does. How do I convert System.Diagnostics.ThreadState to System.Threading.ThreadState, or is it some other method to check it? I'm not trying to suspend/resume them, just I want to know how Process hacker/Process explorer does that.

Answer 1

Microsoft made a big mistake in .NET version 1.0, they added the Thread.Suspend() and Resume() methods. Those methods were widely abused, programmers used them to implement thread synchronization. For which they are entirely inappropriate. Problem was that it usually worked. But call Suspend() at an unlucky time and you'll freeze a thread while it is buried inside a Windows call, holding a global lock. And causing the entire program to deadlock.

It was not the only design mistake they made, the Synchronized method on the collection classes was quite a disaster as well. Widely misinterpreted as "returns a thread-safe collection".

Live and learn, this all got fixed in .NET 2.0. One big overhaul was that a Thread may not necessarily be an operating system thread anymore, that never actually got implemented. But explains why there are two ThreadState enumerations, one for Thread (the .NET version) and another for ProcessThread (the operating system version). And they closed the loophole on programmers abusing Suspend/Resume, the methods were declared obsolete. And they closed the backdoor as well, you can't find out from ProcessThread that a thread is suspended.

Feature, not a bug. Don't make the same mistake, knowing that a thread is suspended is useless knowledge, it may well not be suspended anymore a microsecond later.