Re: threading question

From:
"William DePalo [MVP VC++]" <willd.no.spam@mvps.org>
Newsgroups:
microsoft.public.vc.language
Date:
Fri, 6 Oct 2006 12:58:04 -0400
Message-ID:
<eE7OYiW6GHA.4568@TK2MSFTNGP02.phx.gbl>
"scott mcfadden" <nospam.smcfadden@criticaltech.com> wrote in message
news:ucq6lXW6GHA.4404@TK2MSFTNGP04.phx.gbl...

C# has a easy way of waking another thread (Thread.Interupt). Does C++
/MFC have a nice way of checking the status of another thread and if it is
sleeping, to wake it?


There are two answers to this question, yes and no. :-)

You see there are innumerable things which might cause a thread to wait. It
could be waiting on a mutex, an event, a semaphore, a device handle etc. To
wake it up, you raise the condition whose absence causes the thread to wait.

In addition, Win32 has a rich suite of synchronization primitives that allow
a thread to wait for one of, or all of, a set of conditions. In the "one of"
case, you can dedicate an event to the "it's time stop waiting condition"
and signal it.

So, in short, if you know why a thread is waiting, it is usually a simple
matter to roust it from its slumber. But since there are _so_ many things
which a thread executing native code can be waiting on, as a practical
matter you need to know which threads are doing what.

It's not the C# language that makes this easy in that language. Rather it is
that C# targets a "managed" environment where there is more knowledge about
what is going on because some native flexibility has been removed.

So, what is it that your waiting thread is doing exactly?

Regards,
Will

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