[zeromq-dev] Question about ROUTER queue (what if client dies)

[Goswin von Brederlow]

On Mon, Jul 28, 2014 at 02:42:50PM +0100, Pedro Januário wrote:
> hi Peter,
> 
> I didn???t write C code for a while, but would be something like this:
> 
> #include <czmq.h>
> int main (void)
> {
>      zsock_t *router = zsock_new_router ("tcp://127.0.0.1:9990");
>      zsock_t *dealer = zsock_new_dealer ("tcp://127.0.0.1:9990");
> 
> 
>      // dealer send message
>      zstr_send (dealer, "Hello World");
>      // router received message
>      zmsg_t *msg = zmsg_recv (router);
>      zmsg_print (msg);
>      // dealer (client) disconnects permanently
>      zsock_destroy (&dealer);
>      // router send message to dealer, because it thinks that is connected
>      zmsg_send (&msg, router);
> 
>      zmsg_destroy (&msg);
>      zsock_destroy (&router);
>      return 0;
> }
> 
> I hope this is self explanatory.
> 
> One way to solve this, is by sending ???good bye??? message from dealer (client), but for my use case would be enough discharge message that are send after x minutes.
> 
> 
> Regards,
> 
> Pedro Januário Delivering Innovation and Technology

That case is simple. The DEALER	 shuts down normally so the tcp socket
sends its FIN and the ROUTER removes the outgoing pipe.

But what if the DEALER deadlocks or the kernel crashes (asumming
different systems)? Then tcp will not close the connection for a long
time.

MfG
	Goswin