[zeromq-dev] Perennial thread safety question

[Matthew Woehlke]

On 2013-04-08 16:12, Charles Remes wrote:
> On Apr 8, 2013, at 12:40 PM, Matthew Woehlke wrote:
>> Is it safe to create and set up, and tear down, my 0MQ socket in the
>> ctor/dtor (i.e. in thread A, and poll/recv/etc. in thread B)? Is there
>> something I should be doing to make it safe?
>
> This is answered in the FAQ (http://www.zeromq.org/area:faq). Short answer is: Yes, go ahead and do this. If it crashes, protect the socket with some kind of memory barrier (e.g. mutex).

Ah... I think I may have seen that at some point. However I was 
specifically remembering reading this in the guide:

"Don't share ØMQ sockets between threads. ØMQ sockets are not 
threadsafe. Technically it's possible to migrate a socket from one 
thread to another but it demands skill. The only place where it's 
remotely sane to share sockets between threads are in language bindings 
that need to do magic like garbage collection on sockets."

...which seems to contradict the FAQ. Maybe some less scary text should 
be used? (As I read the FAQ, it's perfectly safe to migrate a socket 
just as long as the migration is 'clean', e.g. memory gets synchronized 
between the last access by thread A and before the first access by 
thread B.)

-- 
Matthew