Killing threads (was Re: Cancel or timeout a long running regular expression)

[Gregory Ewing]

Ian Kelly wrote:

> And what if the thread gets killed a second time while it's in the except block?

> And what if the thread gets killed in the middle of the commit?

For these kinds of reasons, any feature for raising asynchronous
exceptions in another thread would need to come with some related
facilites:

* A way of blocking asynchronous exceptions around a critical
   section would be needed.

* Once an asynchronous exception has been raised, further
   asynchronous exceptions should be blocked until explicitly
   re-enabled.

* Asynchronous exceptions should probably be disabled initially
   in a new thread until it explicitly enables them.

Some care would still be required to write code that is robust
in the presence of asynchronous exceptions, but given these
facilities, it ought to be possible.

-- 
Greg