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

[Roy Liu]

Hi  Luke

Thanks for your advice and i will have a try.


On Fri, Aug 9, 2013 at 9:57 AM, Lucas Hope <lucas.r.hope at gmail.com> wrote:

> Hi again,
>
> Sorry, it is important that the first struct member is a char array (char
> arr[10]), and not a char pointer (char *ptr), as arr gets encoded directly
> as part of the struct, but the ptr does not.
>
> Luke
>
>
> On Fri, Aug 9, 2013 at 11:54 AM, Lucas Hope <lucas.r.hope at gmail.com>wrote:
>
>> 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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>>> zeromq-dev at lists.zeromq.org
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>>>
>>>
>>
>>
>> --
>> ---------------------------------------------------
>> Dr Lucas Hope - lucas.r.hope at skype
>> Machine Learning and Software Engineering Consultant
>> Melbourne, Australia
>>
>
>
>
> --
> ---------------------------------------------------
> Dr Lucas Hope - lucas.r.hope at skype
> Machine Learning and Software Engineering Consultant
> Melbourne, Australia
>
> _______________________________________________
> zeromq-dev mailing list
> zeromq-dev at lists.zeromq.org
> http://lists.zeromq.org/mailman/listinfo/zeromq-dev
>
>
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