ROUTER/DEALER report socket type as XREP/XREQ
Description
Environment
OSX 10.7, llvm-gcc-4.2, etc., libzmq-3.0 git.
Activity
PieterP September 6, 2011 at 1:32 PM
Ah, ok. In fact we don't use that behavior anywhere afaik, and it's not documented, so doesn't merit any special status.
Martin Sustrik September 6, 2011 at 1:18 PM
The semantics are not exactly the same. For example XREP socket drops the queued requests from the peer that disconnects – assuming that there's nobody to receive replies anyway. ROUTER keeps the requests, preserving the 2.x behaviour.
PieterP September 6, 2011 at 1:12 PM
Patch applied to 3-0 master. However it's a little confusing to have both sets of names available, where ZMQ_XREP != ZMQ_ROUTER, but with exactly the same semantics.
It's still unclear to me what the "device API" is meant to be, where this is defined, who is expected to use it, when, etc. "All socket types starting with X are for internal use in devices only" isn't really sufficient.
Martin Sustrik September 6, 2011 at 7:29 AM
Patch sent to the mailing list.
router.getsockopt(TYPE) returns 6 (XREP), and dealer.getsockopt(TYPE) returns 5 (XREQ) in libzmq-3.0 git. So ROUTER/DEALER and XREP/XREQ sockets are indistinguishable.
Example in C:
#include <stdio.h> #include <stdarg.h> #include "zmq.h" int main (int argc, char const *argv[]) { void *context = zmq_init (1); void *router = zmq_socket (context, ZMQ_ROUTER); void *dealer = zmq_socket (context, ZMQ_DEALER); int type; size_t sz = sizeof(type); zmq_getsockopt(router, ZMQ_TYPE, &type, &sz); printf("router type reports %d, while ZMQ_ROUTER=%d\n", type, ZMQ_ROUTER); zmq_getsockopt(dealer, ZMQ_TYPE, &type, &sz); printf("dealer type reports %d, while ZMQ_DEALER=%d\n", type, ZMQ_DEALER); zmq_close (router); zmq_close (dealer); zmq_term (context); } // output: router type reports 6, while ZMQ_ROUTER=11 dealer type reports 5, while ZMQ_DEALER=12These would appear to be the only cases.