[zeromq-dev] What is exactly an empty message
Majid Azimi
azimi.majid at yahoo.com
Sun Feb 3 06:53:22 CET 2013
Hi guys,
I'm a bit confused with examples in Code Connected book.
In the book when it want to send an empty message as delimiter frame it uses:
zmq_send(socket, "", 0, 0);
This is not an empty message. it has body the length is just zero. I thought an empty message is:
zmq_msg_t msg;
zmq_msg_init(&msg);
zmq_msg_send(&msg, socket, 0);
So what is exactly an empty message?
Second question is about ZMQ_SUBSCRIBE. The book uses zero length string "" as a filter to get all messages:
zmq_setsocketopt(socket, ZMQ_SUSCRIBE, "", 0);
But in web sites I have seen examples like this:
zmq_setsocketopt(socket, ZMQ_SUSCRIBE, NULL, 0);
It may be related to first question. Which one is correct?
Thank you very much.
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