On Wed, 31 Jul 1996, Lex Spoon wrote:
> Allowing threads to share pid's means we have to go through and rethink
> what a lot of things mean. Do kill() and waitpid() operate on just
> one thread or all of them? People are going to sometimes want each
> of these cases, so we have to expand kill() and waitpid() to deal
> with it.
>
> Unix already has a way of dealing with a group of cooperating processes:
> process groups. Why not just use this concept for threads, too? If you
> want to kill all the threads in certain process group 37, you do
> kill(-37, SIGWHATEVER).
>
> I CAN see possible uses for wanting to address a "group of threads
> sharing the same memory mappings". But most often, aren't processes and
> process groups just what most people want?
Allowing user mode threads to share pids is probably a mistake. For the
purpose of process control, it probably makes more sense to regard them as
special cases of processes, i.e., processes with shared memory.
Let's not make life any more complicated than it has to be....
lilo
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