[zeromq-dev] zeromq-dev Digest, Vol 24, Issue 13

[Luca Boccassi]

On 24 March 2018 16:10:41 GMT+00:00, "Georger, Joseph" <joseph.georger at stresearch.com> wrote:
>I have looked at the self test and did not see an example where frames
>were being written and a picture received. Here is what happens when I
>run the code below. As you can see, only the string comes through when
>sending frames to a picture.
>
>Testing picture to picture send/receive:
>Sending 5, topic, 3
>Received 5, topic, 3
>Testing frame to picture send/receive:
>Received 0, topic, 0
>
>#include "czmq.h"
>#include <iostream>
>
>int main(void) {
>	// Create two PAIR sockets and connect over inproc
>	zsock_t *output = zsock_new_pair("@inproc://zsock.test");
>	assert (output);
>	zsock_t *input = zsock_new_pair(">inproc://zsock.test");
>	assert (input);
>	
>	// picture to picture test
>	std::cout << "Testing picture to picture send/receive:\n";
>	int num1 = 5;
>	uint32_t num2 = 3;
>	std::cout << "Sending " << num1 << ", topic, " << num2 << std::endl;
>	zsock_send(output, "is4", num1, "topic", num2);
>
>	int rnum1;
>	char *rstr;
>	uint32_t rnum2;
>	int rc = zsock_recv(input, "is4", &rnum1, &rstr, &num2);
>	assert(rc == 0);
>	std::cout << "Received " << rnum1 << ", " << rstr << ", " << num2 <<
>std::endl;
>	freen(rstr);
>
>	// frames to picture test
>	std::cout << "Testing frame to picture send/receive:\n";
>	zmsg_t *msg = zmsg_new();
>	assert(msg);
>	rc = zmsg_addmem(msg, &num1, sizeof(num1));
>	assert(rc == 0);
>	rc = zmsg_addmem(msg, "topic", 5);
>	assert(rc == 0);
>	rc = zmsg_addmem(msg, &num2, sizeof(num2));
>	assert(rc == 0);
>	rc = zmsg_send(&msg, output);
>	assert(rc == 0);
>
>	rnum1 = 0;
>	rnum2 = 0;
>	rc = zsock_recv(input, "is4", &rnum1, &rstr, &num2);
>	assert(rc == 0);
>	std::cout << "Received " << rnum1 << ", " << rstr << ", " << num2 <<
>std::endl;
>	freen(rstr);
>
>	zsock_destroy(&input);
>	zsock_destroy(&output);
>}
>
>Thanks,
>Joe
> 
>
>    
>    Message: 13
>    Date: Sat, 24 Mar 2018 10:11:02 +0000
>    From: Luca Boccassi <luca.boccassi at gmail.com>
>    To: ZeroMQ development list <zeromq-dev at lists.zeromq.org>
>    Subject: Re: [zeromq-dev] zframe compatible w/zsock picture?
>    Message-ID: <1521886262.14111.85.camel at gmail.com>
>    Content-Type: text/plain; charset="utf-8"
>    
>    On Fri, 2018-03-23 at 22:25 +0000, Georger, Joseph wrote:
>  > Just a quick question, I was starting to write send & receive using
>    > zframes, but came across the ?picture? concept in zsock. I was
>    > sending three zframes, using addmem to construct the zmsg: char *
>    > topic, uint32_t length in bytes, char * for msg.
>    > 
>    > I wrote the receiver using pictures,
>    > zsock_receive(socket, ?s4s?, &sz, &topic, &payload)
>    > 
>  > topic came through, but sz was 0. Should this in theory work, can I
> > receive a frame containing a uint32_t with the picture paradigm? Can
>    > I intermix a zmsg/zframe sender with a picture receiver (and vice
>> versa)? The docs imply yes: ?The picture is a string that defines the
>    > type of each frame.?
>    > 
>    > Thanks,
>    > Joe
>    
>    Yes, see selftest for an example:
>    
>https://github.com/zeromq/czmq#zsock---high-level-socket-api-that-hides-libzmq-contexts-and-sockets
>    
>    -- 
>    Kind regards,
>    Luca Boccassi
>    -------------- next part --------------
>    A non-text attachment was scrubbed...
>    Name: signature.asc
>    Type: application/pgp-signature
>    Size: 488 bytes
>    Desc: This is a digitally signed message part
>URL:
><https://lists.zeromq.org/pipermail/zeromq-dev/attachments/20180324/07c46638/attachment-0001.sig>
>    
>    ------------------------------
>    
>    Subject: Digest Footer
>    
>    _______________________________________________
>    zeromq-dev mailing list
>    zeromq-dev at lists.zeromq.org
>    https://lists.zeromq.org/mailman/listinfo/zeromq-dev
>    
>    
>    ------------------------------
>    
>    End of zeromq-dev Digest, Vol 24, Issue 13
>    ******************************************
>    
>
>_______________________________________________
>zeromq-dev mailing list
>zeromq-dev at lists.zeromq.org
>https://lists.zeromq.org/mailman/listinfo/zeromq-dev

Right, you have to use the zsock-recv/send APIs together - look at the implementation if you want to replicate it manually but note that it's not a public protocol so it's not guaranteed to stay unchanged. Those APIs are intended as a self-contained shortcut.