How can I do sethook() to all coroutines of a Lua state?

[Oliver Kroth <oliver.kroth@...>]

I have an (Lua) script that (successfully) uses COPAS to run several 
threads using TCP/IP.
However, when I try to stop the scipt with the mehtod of lua.c by 
hooking an error-generating function, only one thread is stopped.
The other threads continue on their own. Quite puzzling...
I found that each thread has its own hook point, so I am ready to hook 
them all up,
but I haven't figured out yet how to access them (iterate over them).

Does anyone know how?
--
Oliver