[zeromq-dev] question about message buffer

[Mohit Jaggi]

This is not fully full but more detailed...'buf' is on stack (so destructor
will be called) and 'm' is on heap(and I havn't called delete...should I?).
I want to understand how zmq treats them.

context_t ctx(1);

socket_t *publisher;

void init() {

publisher = new socket....

publisher.bind(...)

}

void publish(myObject) {

string buf;

myObject.SerializeToString(&buf);

message_t m = new message_t(buf.size());

memcpy((*void**) m.data(), buf.c_str(), buf.size());

string topic(string("X") + string("Y") + string("Z"));

publisher->send(topic.c_str(), topic.size(), ZMQ_SNDMORE); //topic

publisher->send(m); //data

}

main() {

init();

...

publish(obj);

}


On Mon, Mar 4, 2013 at 12:51 AM, Pieter Hintjens <ph at imatix.com> wrote:

> Hi Mohit,
>
> Can you provide a full example?
>
> -Pieter
>
>
> On Mon, Mar 4, 2013 at 8:34 AM, Mohit Jaggi <mohitjaggi at gmail.com> wrote:
> > Hi,
> > I am a little confused about how messages and buffers are handled in
> zmq. In
> > the following example, valgrind finds a message leak for 'm'.
> > 1) Should I call delete for 'm' after the send?
> > 2) zmq will keep the buffer(data) but free memory for 'm' if I do this?
> > 3) What about 'topic'? It is on stack and data is small, so I guess it
> uses
> > the vsm area to store the message?
> > 4) Will send for 'topic' make a copy of the data then?
> >
> > Mohit.
> >
> >
> > string buf;
> >
> > myObject.SerializeToString(&buf);
> >
> > message_t m = new message_t(buf.size());
> >
> > memcpy((void*) m.data(), buf.c_str(), buf.size());
> >
> > string topic(string("X") + string("Y") + string("Z"));
> >
> > publisher->send(topic.c_str(), topic.size(), ZMQ_SNDMORE); //topic
> >
> > publisher->send(m); //data
> >
> >
> > _______________________________________________
> > zeromq-dev mailing list
> > zeromq-dev at lists.zeromq.org
> > http://lists.zeromq.org/mailman/listinfo/zeromq-dev
> >
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