[zeromq-dev] How to set filter for struct type

[Lucas Hope]

Hi there,

I don't know 100%. Subscriptions are prefix based. The way structs work in
C is that they are packed according to member order. If your first struct
member was a cstring (char *, null-terminated), then the subscription
prefix should match that okay.  I'm not sure how C++ strings are
represented. It might still work if they hold the char buffer at the front.

I hope that helps. I'm not that qualified to answer, really.

Cheers,

Luke


On Fri, Aug 9, 2013 at 11:06 AM, Roy Liu <liuchuanbo at gmail.com> wrote:

> Anyone knows?
> I can not find documents about the filter format according to different
> data type.
>
>
> On Thu, Aug 8, 2013 at 10:30 PM, <liuchuanbo at gmail.com> wrote:
>
>> Hi, everyone
>>
>> On PUB side: wd is struct type message and I send it to the subscriber.
>> typedef struct tag_StructData
>> {
>> string name;
>> }StructData;
>>
>> StructData wd;
>> //  Prepare our context and publisher
>> zmq::context_t context (1);
>> zmq::socket_t publisher (context, ZMQ_PUB);
>> int msgSize = sizeof(wd);
>> zmq::message_t message(msgSize);
>> memcpy ((void *) message.data(), &wd, msgSize);
>> publisher.send(message);
>>
>>
>> On SUB side:
>> // Receive Everything
>> subscriber.setsockopt(ZMQ_SUBSCRIBE, NULL, 0);
>>
>> *// How to set a filter to receive the struct message with the specified
>> name, for example "ABC".*
>>
>>
>> //string msg;
>>  StructData *msg;
>> while(true){
>>  zmq::message_t m;
>> subscriber.recv(&m);
>>  msg = (StructData *)m.data();
>> cout << msg->Symbol << endl;
>>  }
>>
>>
>> Thanks.
>>
>> --
>> Best Regards,
>> Roy Liu
>>
>>
>
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>


-- 
---------------------------------------------------
Dr Lucas Hope - lucas.r.hope at skype
Machine Learning and Software Engineering Consultant
Melbourne, Australia
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