[zeromq-dev] equivalent of accept

Martin Sustrik sustrik at 250bpm.com
Sun Apr 25 15:58:13 CEST 2010

Varol Okan wrote:

>> I think there's a conceptual gap here. 0MQ is not connection based,
>> it's message based. Forget about connections. There are none -- at
>> least from user's point of view. Instead, there are messages.
>> In your case it means there's no way to authenticate a connection.
>> You have to authenticate a message.
> Hahaha, I feel like I was sitting in a dark room until some one
> turned on the light :) Sorry for that, as I said I am starting out
> with 0MQ.


> Anyhow, one last question remains wrt to the client. Since 0MQ is
> message based, how can I determine if the host is alive or simply
> busy doing things.
> Example: for a socket of type  zmq::socket_t socket ( ctx, ZMQ_REQ );
> If I do socket.send ( query ); followed by socket.recv ( &result );
> How do I handle a fault like server crashed, or some one pulled the
> plug. Is there a timeout I can set or would the client freeze ? What
> can I do to gracefully handle these types of fault ?

If a service crashes, 0MQ will remove it from it's load-balancing 
mechanism. Thus messages will be sent to other service instances. If 
there are no other instances, messages will be queued and sent to the 
service once it is restarted.


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