more cancellation work

[David Mosberger]

>>>>> On Wed, 16 Jul 2003 21:11:49 -0700, Richard Henderson <rth@twiddle.net> said:

  Richard> On Tue, Jul 15, 2003 at 04:37:12PM -0700, David Mosberger
  Richard> wrote:
  >> BTW: is there a summary somewhere that libc will be doing?

  Richard> Relying on an external library for the actual unwinding.

What I meant is: when will libc unwind?  As a result of
pthread_cancel()?  If so, how does it work precisely?

But since you brought it up: what API will this "external library"
follow?  The C++ exception handling API? (_Unwind_FOO)?

	--david