Subj : Re: Pre-empting a user-space thread...
To   : comp.programming.threads
From : lindahlb
Date : Mon Jan 31 2005 04:15 pm


Scott Stoddard wrote:
> Thread newbie question here...
>
> I want to set up a timer thread and a 'bunch' of other execution
> threads.  When the timer thread 'comes due' I would like it to
preempt
> the currently executing one of the 'other' threads.  Basically, I
need
> to roll my own scheduler for a project that I'm working on and this
is
> my current idea about how to do it.
>
> I have looked into the pthread library and all the info that I can
> find on nptl and can't find out if this is possible (I'm therefore
> assuming that it is not).  Could anyone tell me if this is
> possible...or, if not, what might be another way to go here?
>
> Thanx,
> Scott.

If you've created your own user threads (via some unportable method
such as setjmp/longjmp), you can use SIGALARM to fire off at
pre-emption times and utilize unportable methods to set the return
context. I've heard of this being done, but I'm unaware of a good means
to change contexts on return from signal handler. Just in case that
helps...

.