Re: [RFC][PATCH] _UC_TLSBASE for all ports

["Valeriy E. Ushakov" <uwe%stderr.spb.ru@localhost>]

On Fri, Aug 10, 2012 at 10:19:03 -0700, Matt Thomas wrote:

> On Aug 10, 2012, at 9:58 AM, Joerg Sonnenberger wrote:
> 
> > On Fri, Aug 10, 2012 at 04:36:17PM +0000, Emmanuel Dreyfus wrote:
> >> Summary of the previous episode: NetBSD's swapcontext restores the
> >> thread_self pointer. When using swapcontext() on a context obtained 
> >> from getcontext() in another thread, this makes two threads with the
> >> same pthread_self, leading to chaos
> > 
> > I maintain that trying to move contexts between threads is an inherently
> > bad idea and that it is a very inefficient interface for implementing
> > coroutines. I object to this change for the sake of misdesigned
> > software.
> 
> I concur.  A thread's stack is its identity and one can't swap stacks
> without swapping its sense of self.  (granted thread local storage
> helps but that isn't universally available).

+1

I'm not sure it's possible to come up with coherent semantic for
mixing pthreads and *context functions in that way (even if stack is
not used as thread identity).

-uwe