From: nobu.nokada@...
Date: 2003-10-09T07:36:33+09:00
Subject: Re: Standard Queue Implementation and Thread Safety

Hi,

At Thu, 9 Oct 2003 03:49:48 +0900,
Pete Kazmier wrote:
> The implementation is essentially backed by an Array.  Queue provides
> synchronized push and pop methods (using Thread.critical), but methods
> such as clear, length, and empty? are not synchronized.  What happens
> if one thread is in the middle of clearing the queue and then another
> comes along to add/remove something from the queue?  Why don't these
> other methods need synchronization?  Is Array thread-safe by default?

Yes.  Builtin methods (more accurately, not written in Ruby)
are thread-safe, unless GC runs.  Since Array#empty? and
Array#length don't modify anything, and Array#clear just
releases but requires no memory, GC doesn't get run.

-- 
Nobu Nakada