Messages in this thread |  | | Date | Fri, 16 Aug 2002 13:34:56 +0100 | From | Jamie Lokier <> | Subject | Re: [patch] user-vm-unlock-2.5.31-A2 |
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Ingo Molnar wrote: > non-POSIX programming methods like JVMs can still implement *any* > semantics - but your whole example is based on POSIX issues like exit() or > default signal handlers, not Java.
Sorry if I was unclear. I'm specifically talking about non-POSIX threading methods (normal C code though, not complicated JVMs).
Most uses of clone() that I've seen are not using any threading library at all: some code that neads a helper thread calls clone(), and the child does its own self-contained system calls (to avoid errno pollution).
It's conceptually fine that individual threads can die. _Conceptually_, clone-by-hand threads are very similar to processes, and I have seen this used in practice a few times.
And it all works fine: just use SIGCHLD and waitpid().
Now you have written this wonderful resource optimisation, which removes zombies: CLONE_DETACHED. Unfortunately, catching invidual thread death relies on the thread "exiting politely", as they say. So I still have to use SIGCHLD and waitpid(), or a pipe(), for non-POSIX-model threads that want to robustly detect "impolite" thread death.
I think that's an unfair penalty on non-POSIX-model threads.
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