From: Wladimir Mutel <mwg@...>
Date: 2002-03-30T00:32:55+09:00
Subject: Re: Threads in Iterators

� ������ <001d01c1d6c0$26318910$dd31200a@JAZZ> Norman Makoto Su �������(�):

>> If you are concerned about this, then use a mutex around code that might
>> corrupt your data:
>>
>>   m = Mutex.new
>>   arr.each do |val|
>>     @mutex.synchronize do
>>       vals << val
>>     end
>>   end
>>
>> I think appending onto vals like this should be an atomic operation (so
>> the mutex isn't necessary), but if you had a non-atomic operation, then
>> you would definitely need a mutex.
> 
> How do I know what operations are atomic operations in ruby?  I guess I should
> assume, unless explicitly specified, that all operations in ruby are not atomic.

	Builtin library methods might be made reentrant/atomic with their side
	effects, but they are too easy to redefine, so may be you should not
	rely on that much and do your own syncronization with mutexes.