[zeromq-dev] Problems with 2.0.6 poll using C++ api

gonzalo diethelm gdiethelm at dcv.cl
Fri Mar 19 12:17:08 CET 2010

> 2. Have a look at dispatcher.cpp, lines 146-154. The code there is
> called when socket is created. It checks whether there's another
> belonging to the same thread and if so, it chooses to share the same
> app_thread_t object. Something probably goes wrong there. Can you
> it? Maybe current thread ID as returned by thread_t::id() is different
> even if called twice from the same thread? Maybe thread ID comparison
> function, thread_t::equal() is broken and returns false even if the
> thread IDs are the same?

I took a look at that code. The only thing I noticed is that it will
fill the app_threads array "backwards", from N-1, N-2, ..., to 0. But I
don't think that really matters.

I also thought it was weird to see the for statement using a !=
comparison. I would probably have written it like this, with a <:

  for (current = 0; current < app_threads.size (); current++) {...}

But that, also, doesn't make any difference.

Finally, I looked at thread_t::equal (). It compares the two thread ids
with ==; however, for non-Windows Oss, the thread ids are of type
pthread_t, and those objects should be compared with pthread_equal ().
Therefore, I would change line 46 in thread.cpp to this:

bool zmq::thread_t::equal (id_t id1_, id_t id2_)
    return id1_ == id2_;
    return pthread_equal (id1_, id2_);

This is non-tested (I am running on Windows here) and submitted
MIT-licensed, for whatever it is worth. Best regards.

Gonzalo Diethelm

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