one question about l4_thread_ex_regs flags

[Guanghui, Cheng]

> The output will always come from the same thread so the output should
> always be the same?!
> L4_THREAD_EX_REGS_RAISE_EXCEPTION is in effect once,
> L4_THREAD_EX_REGS_ALIEN is a permanent state of the thread. If you do
> not set it in a following exregs call it's cleared again. If you do a
> trigger-exception, you get an exception IPC, if you do it again, you get
> the next. But exception IPC is also about sending a reply, so you need
> to reply to the receiving IPC to allow the thread to continue.
	 L4_THREAD_EX_REGS_RAISE_EXCEPTION flag needs to bet set every time. But 
L4_THREAD_EX_REGS_ALIEN doesn't need.	My test program could run as what i 
want to do.
	But what is the difference between L4_THREAD_EX_REGS_ALIEN and 
L4_THREAD_EX_REGS_RAISE_EXCEPTION|L4_THREAD_EX_REGS_ALIEN?
	In the L4Linux i found you use L4_THREAD_EX_REGS_RAISE_EXCEPTION|
L4_THREAD_EX_REGS_ALIEN but not only L4_THREAD_EX_REGS_ALIEN? What 
considerations do you have?
	Thanks a lot.
									cheng guanghui