Question

My model of how threads work is that some ThreadManager gives each thread a turn. When it’s a thread’s turn, it gets to execute a few lines of code.

To pause a thread, couldn’t one just have the ThreadManager (momentarily) stop allowing that thread to have a turn?

To abort a thread, couldn’t the ThreadManager just never give that thread another turn?

What’s the problem?

Answer 1

Quote from MSDN about pausing threads:

You have no way of knowing what code a
thread is executing when you suspend
it. If you suspend a thread while it
holds locks during a security
permission evaluation, other threads
in the AppDomain might be blocked. If
you suspend a thread while it is
executing a class constructor, other
threads in the AppDomain that attempt
to use that class are blocked.
Deadlocks can occur very easily.

Aborted thread can lead to unpredicted circumstances. There is a good article about this: http://www.bluebytesoftware.com/blog/2009/03/13/ManagedCodeAndAsynchronousExceptionHardening.aspx