[nanomsg] Re: publish/subscribe keys
- From: Dirkjan Ochtman <dirkjan@xxxxxxxxxx>
- To: nanomsg <nanomsg@xxxxxxxxxxxxx>
- Date: Wed, 13 Aug 2014 23:08:03 +0100
On Wed, Aug 13, 2014 at 9:47 PM, John Carneiro <johncarneiro@xxxxxxxxxxx> wrote:
> It seems like this line from the example:
> nn_setsockopt (sock, NN_SUB, NN_SUB_SUBSCRIBE, "", 0)
>
> could easily be instead something like this to subscribe to a subscription
> type of "sub1":
> const char* subType = "sub1";
> nn_setsockopt (sock, NN_SUB, NN_SUB_SUBSCRIBE, subType, strlen(subType) + 1)
Yes, that's about right.
> and I would assume you could read this string on the publishing server like
> this
> char subType[100];
> getsockopt(sock, NN_SOL_SOCKET, NN_PROTOCOL, &subType, sizeof(subType));
But that is not. For now, subscriptions on the NN_SUB side of the
protocol (there may be more than one, theoretically as many as you
like) are matched against the actual message sent by the NN_PUB side.
So, if you're subscribing to "sub1\0", a message containing "sub1\0a"
from the publisher will be received, whereas a message containing
"sub2" will not.
Hopefully that's enough information to get your example working, do
ask more questions if that turns out not to be the case.
Cheers,
Dirkjan
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