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instance method

Queue#close

static VALUE
rb_queue_close(VALUE self)
{
    struct rb_queue *q = queue_ptr(self);

    if (!queue_closed_p(self)) {
        FL_SET(self, QUEUE_CLOSED);

        wakeup_all(queue_waitq(q));
    }

    return self;
}

Closes the queue. A closed queue cannot be re-opened.

After the call to close completes, the following are true:

closed? will return true
close will be ignored.
calling enq/push/<< will raise a ClosedQueueError.
when empty? is false, calling deq/pop/shift will return an object from the queue as usual.
when empty? is true, deq(false) will not suspend the thread and will return nil. deq(true) will raise a ThreadError.

ClosedQueueError is inherited from StopIteration, so that you can break loop block.

Example:

    q = Queue.new
    Thread.new{
      while e = q.deq # wait for nil to break loop
        # ...
      end
    }
    q.close