1ZMQ_SETSOCKOPT(3) 0MQ Manual ZMQ_SETSOCKOPT(3)
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6 zmq_setsockopt - set 0MQ socket options
7
9 int zmq_setsockopt (void *socket, int option_name, const void
10 *option_value, size_t option_len);
11 Caution: All options, with the exception of ZMQ_SUBSCRIBE,
13 ZMQ_UNSUBSCRIBE, ZMQ_LINGER, ZMQ_ROUTER_HANDOVER, ZMQ_ROUTER_MANDATORY,
14 ZMQ_PROBE_ROUTER, ZMQ_XPUB_VERBOSE, ZMQ_XPUB_VERBOSER,
15 ZMQ_REQ_CORRELATE, ZMQ_REQ_RELAXED, ZMQ_SNDHWM and ZMQ_RCVHWM, only
16 take effect for subsequent socket bind/connects.
17 Specifically, security options take effect for subsequent bind/connect
19 calls, and can be changed at any time to affect subsequent binds and/or
20 connects.
21
23 The zmq_setsockopt() function shall set the option specified by the
24 option_name argument to the value pointed to by the option_value
25 argument for the 0MQ socket pointed to by the socket argument. The
26 option_len argument is the size of the option value in bytes. For
27 options taking a value of type "character string", the provided byte
28 data should either contain no zero bytes, or end in a single zero byte
29 (terminating ASCII NUL character).
30 The following socket options can be set with the zmq_setsockopt()
32 function:
33 ZMQ_AFFINITY: Set I/O thread affinity
35 The ZMQ_AFFINITY option shall set the I/O thread affinity for newly
36 created connections on the specified socket.
37 Affinity determines which threads from the 0MQ I/O thread pool
39 associated with the socket’s context shall handle newly created
40 connections. A value of zero specifies no affinity, meaning that work
41 shall be distributed fairly among all 0MQ I/O threads in the thread
42 pool. For non-zero values, the lowest bit corresponds to thread 1,
43 second lowest bit to thread 2 and so on. For example, a value of 3
44 specifies that subsequent connections on socket shall be handled
45 exclusively by I/O threads 1 and 2.
46 See also zmq_init(3) for details on allocating the number of I/O
48 threads for a specific context.
49 Option value type uint64_t
52 Option value unit N/A (bitmap)
54 Default value 0
56 Applicable socket types N/A
58 ZMQ_BACKLOG: Set maximum length of the queue of outstanding connections
61 The ZMQ_BACKLOG option shall set the maximum length of the queue of
62 outstanding peer connections for the specified socket; this only
63 applies to connection-oriented transports. For details refer to your
64 operating system documentation for the listen function.
65 Option value type int
69 Option value unit connections
71 Default value 100
73 Applicable socket types all, only for
75 connection-oriented
76 transports.
77 ZMQ_BINDTODEVICE: Set name of device to bind the socket to
80 The ZMQ_BINDTODEVICE option binds this socket to a particular device,
81 eg. an interface or VRF. If a socket is bound to an interface, only
82 packets received from that particular interface are processed by the
83 socket. If device is a VRF device, then subsequent binds/connects to
84 that socket use addresses in the VRF routing table.
85 Note
87 requires setting CAP_NET_RAW on the compiled program.
88 Option value type character string
91 Option value unit N/A
93 Default value not set
95 Applicable socket types all, when using TCP or UDP
97 transports.
98 ZMQ_CONNECT_RID: Assign the next outbound connection id
101 This option name is now deprecated. Use ZMQ_CONNECT_ROUTING_ID instead.
102 ZMQ_CONNECT_RID remains as an alias for now.
103 ZMQ_CONNECT_ROUTING_ID: Assign the next outbound routing id
105 The ZMQ_CONNECT_ROUTING_ID option sets the peer id of the peer
106 connected via the next zmq_connect() call, such that that connection is
107 immediately ready for data transfer with the given routing id. This
108 option applies only to the first subsequent call to zmq_connect(),
109 zmq_connect() calls thereafter use the default connection behaviour.
110 Typical use is to set this socket option ahead of each zmq_connect()
112 call. Each connection MUST be assigned a unique routing id. Assigning a
113 routing id that is already in use is not allowed.
114 Useful when connecting ROUTER to ROUTER, or STREAM to STREAM, as it
116 allows for immediate sending to peers. Outbound routing id framing
117 requirements for ROUTER and STREAM sockets apply.
118 The routing id must be from 1 to 255 bytes long and MAY NOT start with
120 a zero byte (such routing ids are reserved for internal use by the 0MQ
121 infrastructure).
122 Option value type binary data
125 Option value unit N/A
127 Default value NULL
129 Applicable socket types ZMQ_ROUTER, ZMQ_STREAM
131 ZMQ_CONFLATE: Keep only last message
134 If set, a socket shall keep only one message in its inbound/outbound
135 queue, this message being the last message received/the last message to
136 be sent. Ignores ZMQ_RCVHWM and ZMQ_SNDHWM options. Does not support
137 multi-part messages, in particular, only one part of it is kept in the
138 socket internal queue.
139 Note
141 If recv is not called on the inbound socket, the queue and memory
142 will grow with each message received. Use zmq_getsockopt(3) with
143 ZMQ_EVENTS to trigger the conflation of the messages.
144 Option value type int
147 Option value unit boolean
149 Default value 0 (false)
151 Applicable socket types ZMQ_PULL, ZMQ_PUSH,
153 ZMQ_SUB, ZMQ_PUB,
154 ZMQ_DEALER
155 ZMQ_CONNECT_TIMEOUT: Set connect() timeout
158 Sets how long to wait before timing-out a connect() system call. The
159 connect() system call normally takes a long time before it returns a
160 time out error. Setting this option allows the library to time out the
161 call at an earlier interval.
162 Option value type int
165 Option value unit milliseconds
167 Default value 0 (disabled)
169 Applicable socket types all, when using TCP
171 transports.
172 ZMQ_CURVE_PUBLICKEY: Set CURVE public key
175 Sets the socket’s long term public key. You must set this on CURVE
176 client sockets, see zmq_curve(7). You can provide the key as 32 binary
177 bytes, or as a 40-character string encoded in the Z85 encoding format
178 and terminated in a null byte. The public key must always be used with
179 the matching secret key. To generate a public/secret key pair, use
180 zmq_curve_keypair(3). To derive the public key from a secret key, use
181 zmq_curve_public(3).
182 Note
184 an option value size of 40 is supported for backwards
185 compatibility, though is deprecated.
186 Option value type binary data or Z85 text
189 string
190 Option value size 32 or 41
192 Default value NULL
194 Applicable socket types all, when using TCP
196 transport
197 ZMQ_CURVE_SECRETKEY: Set CURVE secret key
200 Sets the socket’s long term secret key. You must set this on both CURVE
201 client and server sockets, see zmq_curve(7). You can provide the key as
202 32 binary bytes, or as a 40-character string encoded in the Z85
203 encoding format and terminated in a null byte. To generate a
204 public/secret key pair, use zmq_curve_keypair(3). To derive the public
205 key from a secret key, use zmq_curve_public(3).
206 Note
208 an option value size of 40 is supported for backwards
209 compatibility, though is deprecated.
210 Option value type binary data or Z85 text
213 string
214 Option value size 32 or 41
216 Default value NULL
218 Applicable socket types all, when using TCP
220 transport
221 ZMQ_CURVE_SERVER: Set CURVE server role
224 Defines whether the socket will act as server for CURVE security, see
225 zmq_curve(7). A value of 1 means the socket will act as CURVE server. A
226 value of 0 means the socket will not act as CURVE server, and its
227 security role then depends on other option settings. Setting this to 0
228 shall reset the socket security to NULL. When you set this you must
229 also set the server’s secret key using the ZMQ_CURVE_SECRETKEY option.
230 A server socket does not need to know its own public key.
231 Option value type int
234 Option value unit 0, 1
236 Default value 0
238 Applicable socket types all, when using TCP
240 transport
241 ZMQ_CURVE_SERVERKEY: Set CURVE server key
244 Sets the socket’s long term server key. You must set this on CURVE
245 client sockets, see zmq_curve(7). You can provide the key as 32 binary
246 bytes, or as a 40-character string encoded in the Z85 encoding format
247 and terminated in a null byte. This key must have been generated
248 together with the server’s secret key. To generate a public/secret key
249 pair, use zmq_curve_keypair(3).
250 Note
252 an option value size of 40 is supported for backwards
253 compatibility, though is deprecated.
254 Option value type binary data or Z85 text
257 string
258 Option value size 32 or 41
260 Default value NULL
262 Applicable socket types all, when using TCP
267 transport
268 ZMQ_DISCONNECT_MSG: set a disconnect message that the socket will generate
271 when accepted peer disconnect
272 When set, the socket will generate a disconnect message when accepted
273 peer has been disconnected. You may set this on ROUTER, SERVER and PEER
274 sockets. The combination with ZMQ_HEARTBEAT_IVL is powerful and
275 simplify protocols, when heartbeat recognize a connection drop it will
276 generate a disconnect message that can match the protocol of the
277 application.
278 Option value type binary data
281 Option value unit N/A
283 Default value NULL
285 Applicable socket types ZMQ_ROUTER, ZMQ_SERVER and
287 ZMQ_PEER
288 ZMQ_GSSAPI_PLAINTEXT: Disable GSSAPI encryption
291 Defines whether communications on the socket will be encrypted, see
292 zmq_gssapi(7). A value of 1 means that communications will be
293 plaintext. A value of 0 means communications will be encrypted.
294 Option value type int
297 Option value unit 0, 1
299 Default value 0 (false)
301 Applicable socket types all, when using TCP
303 transport
304 ZMQ_GSSAPI_PRINCIPAL: Set name of GSSAPI principal
307 Sets the name of the principal for whom GSSAPI credentials should be
308 acquired.
309 Option value type character string
312 Option value unit N/A
314 Default value not set
316 Applicable socket types all, when using TCP
318 transport
319 ZMQ_GSSAPI_SERVER: Set GSSAPI server role
322 Defines whether the socket will act as server for GSSAPI security, see
323 zmq_gssapi(7). A value of 1 means the socket will act as GSSAPI server.
324 A value of 0 means the socket will act as GSSAPI client.
325 Option value type int
328 Option value unit 0, 1
330 Default value 0 (false)
333 Applicable socket types all, when using TCP
335 transport
336 ZMQ_GSSAPI_SERVICE_PRINCIPAL: Set name of GSSAPI service principal
339 Sets the name of the principal of the GSSAPI server to which a GSSAPI
340 client intends to connect.
341 Option value type character string
344 Option value unit N/A
346 Default value not set
348 Applicable socket types all, when using TCP
350 transport
351 ZMQ_GSSAPI_SERVICE_PRINCIPAL_NAMETYPE: Set name type of service principal
354 Sets the name type of the GSSAPI service principal. A value of
355 ZMQ_GSSAPI_NT_HOSTBASED (0) means the name specified with
356 ZMQ_GSSAPI_SERVICE_PRINCIPAL is interpreted as a host based name. A
357 value of ZMQ_GSSAPI_NT_USER_NAME (1) means it is interpreted as a local
358 user name. A value of ZMQ_GSSAPI_NT_KRB5_PRINCIPAL (2) means it is
359 interpreted as an unparsed principal name string (valid only with the
360 krb5 GSSAPI mechanism).
361 Option value type int
364 Option value unit 0, 1, 2
366 Default value 0
368 (ZMQ_GSSAPI_NT_HOSTBASED)
369 Applicable socket types all, when using TCP or IPC
371 transport
372 ZMQ_GSSAPI_PRINCIPAL_NAMETYPE: Set name type of principal
375 Sets the name type of the GSSAPI principal. A value of
376 ZMQ_GSSAPI_NT_HOSTBASED (0) means the name specified with
377 ZMQ_GSSAPI_PRINCIPAL is interpreted as a host based name. A value of
378 ZMQ_GSSAPI_NT_USER_NAME (1) means it is interpreted as a local user
379 name. A value of ZMQ_GSSAPI_NT_KRB5_PRINCIPAL (2) means it is
380 interpreted as an unparsed principal name string (valid only with the
381 krb5 GSSAPI mechanism).
382 Option value type int
385 Option value unit 0, 1, 2
387 Default value 0
389 (ZMQ_GSSAPI_NT_HOSTBASED)
390 Applicable socket types all, when using TCP or IPC
392 transport
393 ZMQ_HANDSHAKE_IVL: Set maximum handshake interval
396 The ZMQ_HANDSHAKE_IVL option shall set the maximum handshake interval
397 for the specified socket. Handshaking is the exchange of socket
398 configuration information (socket type, routing id, security) that
399 occurs when a connection is first opened, only for connection-oriented
400 transports. If handshaking does not complete within the configured
401 time, the connection shall be closed. The value 0 means no handshake
402 time limit.
403 Option value type int
406 Option value unit milliseconds
408 Default value 30000
410 Applicable socket types all but ZMQ_STREAM, only
412 for connection-oriented
413 transports
414 ZMQ_HELLO_MSG: set an hello message that will be sent when a new peer
417 connect
418 When set, the socket will automatically send an hello message when a
419 new connection is made or accepted. You may set this on DEALER, ROUTER,
420 CLIENT, SERVER and PEER sockets. The combination with ZMQ_HEARTBEAT_IVL
421 is powerful and simplify protocols, as now heartbeat and sending the
422 hello message can be left out of protocols and be handled by zeromq.
423 Option value type binary data
426 Option value unit N/A
428 Default value NULL
430 Applicable socket types ZMQ_ROUTER, ZMQ_DEALER,
432 ZMQ_CLIENT, ZMQ_SERVER and
433 ZMQ_PEER
434 ZMQ_HEARTBEAT_IVL: Set interval between sending ZMTP heartbeats
437 The ZMQ_HEARTBEAT_IVL option shall set the interval between sending
438 ZMTP heartbeats for the specified socket. If this option is set and is
439 greater than 0, then a PING ZMTP command will be sent every
440 ZMQ_HEARTBEAT_IVL milliseconds.
441 Option value type int
444 Option value unit milliseconds
446 Default value 0
448 Applicable socket types all, when using
450 connection-oriented
451 transports
452 ZMQ_HEARTBEAT_TIMEOUT: Set timeout for ZMTP heartbeats
455 The ZMQ_HEARTBEAT_TIMEOUT option shall set how long to wait before
456 timing-out a connection after sending a PING ZMTP command and not
457 receiving any traffic. This option is only valid if ZMQ_HEARTBEAT_IVL
458 is also set, and is greater than 0. The connection will time out if
459 there is no traffic received after sending the PING command, but the
460 received traffic does not have to be a PONG command - any received
461 traffic will cancel the timeout.
462 Option value type int
467 Option value unit milliseconds
469 Default value 0 normally,
471 ZMQ_HEARTBEAT_IVL if it is
472 set
473 Applicable socket types all, when using
475 connection-oriented
476 transports
477 ZMQ_HEARTBEAT_TTL: Set the TTL value for ZMTP heartbeats
480 The ZMQ_HEARTBEAT_TTL option shall set the timeout on the remote peer
481 for ZMTP heartbeats. If this option is greater than 0, the remote side
482 shall time out the connection if it does not receive any more traffic
483 within the TTL period. This option does not have any effect if
484 ZMQ_HEARTBEAT_IVL is not set or is 0. Internally, this value is rounded
485 down to the nearest decisecond, any value less than 100 will have no
486 effect.
487 Option value type int
490 Option value unit milliseconds
492 Default value 0
494 Maximum value 6553599 (which is 2^16-1
496 deciseconds)
497 Applicable socket types all, when using
499 connection-oriented
500 transports
501 ZMQ_IDENTITY: Set socket identity
504 This option name is now deprecated. Use ZMQ_ROUTING_ID instead.
505 ZMQ_IDENTITY remains as an alias for now.
506 ZMQ_IMMEDIATE: Queue messages only to completed connections
508 By default queues will fill on outgoing connections even if the
509 connection has not completed. This can lead to "lost" messages on
510 sockets with round-robin routing (REQ, PUSH, DEALER). If this option is
511 set to 1, messages shall be queued only to completed connections. This
512 will cause the socket to block if there are no other connections, but
513 will prevent queues from filling on pipes awaiting connection.
514 Option value type int
517 Option value unit boolean
519 Default value 0 (false)
521 Applicable socket types all, only for
523 connection-oriented
524 transports.
525 ZMQ_INVERT_MATCHING: Invert message filtering
528 Reverses the filtering behavior of PUB-SUB sockets, when set to 1.
529 On PUB and XPUB sockets, this causes messages to be sent to all
531 connected sockets except those subscribed to a prefix that matches the
532 message. On SUB sockets, this causes only incoming messages that do not
533 match any of the socket’s subscriptions to be received by the user.
534 Whenever ZMQ_INVERT_MATCHING is set to 1 on a PUB socket, all SUB
536 sockets connecting to it must also have the option set to 1. Failure to
537 do so will have the SUB sockets reject everything the PUB socket sends
538 them. XSUB sockets do not need to do this because they do not filter
539 incoming messages.
540 Option value type int
543 Option value unit 0,1
545 Default value 0
547 Applicable socket types ZMQ_PUB, ZMQ_XPUB, ZMQ_SUB
549 ZMQ_IPV6: Enable IPv6 on socket
552 Set the IPv6 option for the socket. A value of 1 means IPv6 is enabled
553 on the socket, while 0 means the socket will use only IPv4. When IPv6
554 is enabled the socket will connect to, or accept connections from, both
555 IPv4 and IPv6 hosts.
556 Option value type int
559 Option value unit boolean
561 Default value 0 (false)
563 Applicable socket types all, when using TCP
565 transports.
566 ZMQ_LINGER: Set linger period for socket shutdown
569 The ZMQ_LINGER option shall set the linger period for the specified
570 socket. The linger period determines how long pending messages which
571 have yet to be sent to a peer shall linger in memory after a socket is
572 disconnected with zmq_disconnect(3) or closed with zmq_close(3), and
573 further affects the termination of the socket’s context with
574 zmq_ctx_term(3). The following outlines the different behaviours:
575 • A value of -1 specifies an infinite linger period. Pending messages
577 shall not be discarded after a call to zmq_disconnect() or
578 zmq_close(); attempting to terminate the socket’s context with
579 zmq_ctx_term() shall block until all pending messages have been
580 sent to a peer.
581 • The value of 0 specifies no linger period. Pending messages shall
583 be discarded immediately after a call to zmq_disconnect() or
584 zmq_close().
585 • Positive values specify an upper bound for the linger period in
587 milliseconds. Pending messages shall not be discarded after a call
588 to zmq_disconnect() or zmq_close(); attempting to terminate the
589 socket’s context with zmq_ctx_term() shall block until either all
590 pending messages have been sent to a peer, or the linger period
591 expires, after which any pending messages shall be discarded.
592 Option value type int
594 Option value unit milliseconds
595 Default value -1 (infinite)
596 Applicable socket types all
597 ZMQ_MAXMSGSIZE: Maximum acceptable inbound message size
600 Limits the size of the inbound message. If a peer sends a message
601 larger than ZMQ_MAXMSGSIZE it is disconnected. Value of -1 means no
602 limit.
603 Option value type int64_t
606 Option value unit bytes
608 Default value -1
610 Applicable socket types all
612 ZMQ_METADATA: Add application metadata properties to a socket
615 The ZMQ_METADATA option shall add application metadata to the specified
616 socket, the metadata is exchanged with peers during connection setup. A
617 metadata property is specfied as a string, delimited by a colon,
618 starting with the metadata property followed by the metadata value, for
619 example "X-key:value". Property names are restrited to maximum 255
620 characters and must be prefixed by "X-". Multiple application metadata
621 properties can be added to a socket by executing zmq_setsockopt()
622 multiple times. As the argument is a null-terminated string, binary
623 data must be encoded before it is added e.g. using Z85
624 (zmq_z85_encode(3)).
625 Note
627 in DRAFT state, not yet available in stable releases.
628 Option value type character string
631 Option value unit N/A
633 Default value not set
635 Applicable socket types all
637 ZMQ_MULTICAST_HOPS: Maximum network hops for multicast packets
640 Sets the time-to-live field in every multicast packet sent from this
641 socket. The default is 1 which means that the multicast packets don’t
642 leave the local network.
643 Option value type int
646 Option value unit network hops
648 Default value 1
650 Applicable socket types all, when using multicast
652 transports
653 ZMQ_MULTICAST_MAXTPDU: Maximum transport data unit size for multicast
656 packets
657 Sets the maximum transport data unit size used for outbound multicast
658 packets.
659 This must be set at or below the minimum Maximum Transmission Unit
661 (MTU) for all network paths over which multicast reception is required.
662 Option value type int
665 Option value unit bytes
668 Default value 1500
670 Applicable socket types all, when using multicast
672 transports
673 ZMQ_PLAIN_PASSWORD: Set PLAIN security password
676 Sets the password for outgoing connections over TCP or IPC. If you set
677 this to a non-null value, the security mechanism used for connections
678 shall be PLAIN, see zmq_plain(7). If you set this to a null value, the
679 security mechanism used for connections shall be NULL, see zmq_null(3).
680 Option value type character string
683 Option value unit N/A
685 Default value not set
687 Applicable socket types all, when using TCP
689 transport
690 ZMQ_PLAIN_SERVER: Set PLAIN server role
693 Defines whether the socket will act as server for PLAIN security, see
694 zmq_plain(7). A value of 1 means the socket will act as PLAIN server. A
695 value of 0 means the socket will not act as PLAIN server, and its
696 security role then depends on other option settings. Setting this to 0
697 shall reset the socket security to NULL.
698 Option value type int
701 Option value unit 0, 1
703 Default value 0
705 Applicable socket types all, when using TCP
707 transport
708 ZMQ_PLAIN_USERNAME: Set PLAIN security username
711 Sets the username for outgoing connections over TCP or IPC. If you set
712 this to a non-null value, the security mechanism used for connections
713 shall be PLAIN, see zmq_plain(7). If you set this to a null value, the
714 security mechanism used for connections shall be NULL, see zmq_null(3).
715 Option value type character string
718 Option value unit N/A
720 Default value not set
722 Applicable socket types all, when using TCP
724 transport
725 ZMQ_USE_FD: Set the pre-allocated socket file descriptor
728 When set to a positive integer value before zmq_bind is called on the
729 socket, the socket shall use the corresponding file descriptor for
730 connections over TCP or IPC instead of allocating a new file
731 descriptor. Useful for writing systemd socket activated services. If
732 set to -1 (default), a new file descriptor will be allocated instead
733 (default behaviour).
734 Note
736 if set after calling zmq_bind, this option shall have no effect.
737 NOTE: the file descriptor passed through MUST have been ran through
738 the "bind" and "listen" system calls beforehand. Also, socket
739 option that would normally be passed through zmq_setsockopt like
740 TCP buffers length, IP_TOS or SO_REUSEADDR MUST be set beforehand
741 by the caller, as they must be set before the socket is bound.
742 Option value type int
745 Option value unit file descriptor
747 Default value -1
749 Applicable socket types all bound sockets, when
751 using IPC or TCP transport
752 ZMQ_PRIORITY: Set the Priority on socket
755 Sets the protocol-defined priority for all packets to be sent on this
756 socket, where supported by the OS. In Linux, values greater than 6
757 require admin capability (CAP_NET_ADMIN)
758 Option value type int
761 Option value unit >0
763 Default value 0
765 Applicable socket types all, only for
767 connection-oriented
768 transports
769 ZMQ_PROBE_ROUTER: bootstrap connections to ROUTER sockets
772 When set to 1, the socket will automatically send an empty message when
773 a new connection is made or accepted. You may set this on REQ, DEALER,
774 or ROUTER sockets connected to a ROUTER socket. The application must
775 filter such empty messages. The ZMQ_PROBE_ROUTER option in effect
776 provides the ROUTER application with an event signaling the arrival of
777 a new peer.
778 Note
780 do not set this option on a socket that talks to any other socket
781 types: the results are undefined.
782 Option value type int
785 Option value unit 0, 1
787 Default value 0
789 Applicable socket types ZMQ_ROUTER, ZMQ_DEALER,
791 ZMQ_REQ
792 ZMQ_RATE: Set multicast data rate
795 The ZMQ_RATE option shall set the maximum send or receive data rate for
796 multicast transports such as zmq_pgm(7) using the specified socket.
797 Option value type int
802 Option value unit kilobits per second
804 Default value 100
806 Applicable socket types all, when using multicast
808 transports
809 ZMQ_RCVBUF: Set kernel receive buffer size
812 The ZMQ_RCVBUF option shall set the underlying kernel receive buffer
813 size for the socket to the specified size in bytes. A value of -1 means
814 leave the OS default unchanged. For details refer to your operating
815 system documentation for the SO_RCVBUF socket option.
816 Option value type int
819 Option value unit bytes
821 Default value -1
823 Applicable socket types all
825 ZMQ_RCVHWM: Set high water mark for inbound messages
828 The ZMQ_RCVHWM option shall set the high water mark for inbound
829 messages on the specified socket. The high water mark is a hard limit
830 on the maximum number of outstanding messages 0MQ shall queue in memory
831 for any single peer that the specified socket is communicating with. A
832 value of zero means no limit.
833 If this limit has been reached the socket shall enter an exceptional
835 state and depending on the socket type, 0MQ shall take appropriate
836 action such as blocking or dropping sent messages. Refer to the
837 individual socket descriptions in zmq_socket(3) for details on the
838 exact action taken for each socket type.
839 Note
841 0MQ does not guarantee that the socket will be able to queue as
842 many as ZMQ_RCVHWM messages, and the actual limit may be lower or
843 higher, depending on socket transport. A notable example is for
844 sockets using TCP transport; see zmq_tcp(7).
845 Option value type int
848 Option value unit messages
850 Default value 1000
852 Applicable socket types all
854 ZMQ_RCVTIMEO: Maximum time before a recv operation returns with EAGAIN
857 Sets the timeout for receive operation on the socket. If the value is
858 0, zmq_recv(3) will return immediately, with a EAGAIN error if there is
859 no message to receive. If the value is -1, it will block until a
860 message is available. For all other values, it will wait for a message
861 for that amount of time before returning with an EAGAIN error.
862 Option value type int
865 Option value unit milliseconds
869 Default value -1 (infinite)
871 Applicable socket types all
873 ZMQ_RECONNECT_IVL: Set reconnection interval
876 The ZMQ_RECONNECT_IVL option shall set the initial reconnection
877 interval for the specified socket. The reconnection interval is the
878 period 0MQ shall wait between attempts to reconnect disconnected peers
879 when using connection-oriented transports. The value -1 means no
880 reconnection.
881 Note
883 The reconnection interval may be randomized by 0MQ to prevent
884 reconnection storms in topologies with a large number of peers per
885 socket.
886 Option value type int
889 Option value unit milliseconds
891 Default value 100
893 Applicable socket types all, only for
895 connection-oriented
896 transports
897 ZMQ_RECONNECT_IVL_MAX: Set maximum reconnection interval
900 The ZMQ_RECONNECT_IVL_MAX option shall set the maximum reconnection
901 interval for the specified socket. This is the maximum period 0MQ shall
902 wait between attempts to reconnect. On each reconnect attempt, the
903 previous interval shall be doubled untill ZMQ_RECONNECT_IVL_MAX is
904 reached. This allows for exponential backoff strategy. Default value
905 means no exponential backoff is performed and reconnect interval
906 calculations are only based on ZMQ_RECONNECT_IVL.
907 Note
909 Values less than ZMQ_RECONNECT_IVL will be ignored.
910 Option value type int
913 Option value unit milliseconds
915 Default value 0 (only use
917 ZMQ_RECONNECT_IVL)
918 Applicable socket types all, only for
920 connection-oriented
921 transports
922 ZMQ_RECONNECT_STOP: Set condition where reconnection will stop
925 The ZMQ_RECONNECT_STOP option shall set the conditions under which
926 automatic reconnection will stop. This can be useful when a process
927 binds to a wild-card port, where the OS supplies an ephemeral port.
928 The ZMQ_RECONNECT_STOP_CONN_REFUSED option will stop reconnection when
930 0MQ receives the ECONNREFUSED return code from the connect. This
931 indicates that there is no code bound to the specified endpoint.
932 The ZMQ_RECONNECT_STOP_HANDSHAKE_FAILED option will stop reconnection
934 if the 0MQ handshake fails. This can be used to detect and/or prevent
935 errant connection attempts to non-0MQ sockets. Note that when
936 specifying this option you may also want to set ZMQ_HANDSHAKE_IVL — the
937 default handshake interval is 30000 (30 seconds), which is typically
938 too large.
939 The ZMQ_RECONNECT_STOP_AFTER_DISCONNECT option will stop reconnection
941 when zmq_disconnect() has been called. This can be useful when the
942 user’s request failed (server not ready), as the socket does not need
943 to continue to reconnect after user disconnect actively.
944 Note
946 in DRAFT state, not yet available in stable releases.
947 Option value type int
950 Option value unit 0,
952 ZMQ_RECONNECT_STOP_CONN_REFUSED,
953 ZMQ_RECONNECT_STOP_HANDSHAKE_FAILED,
954 ZMQ_RECONNECT_STOP_CONN_REFUSED
955 |
956 ZMQ_RECONNECT_STOP_HANDSHAKE_FAILED
957 Default value 0
959 Applicable socket types all, only for connection-oriented
961 transports (ZMQ_HANDSHAKE_IVL is not
962 applicable for ZMQ_STREAM sockets)
963 ZMQ_RECOVERY_IVL: Set multicast recovery interval
966 The ZMQ_RECOVERY_IVL option shall set the recovery interval for
967 multicast transports using the specified socket. The recovery interval
968 determines the maximum time in milliseconds that a receiver can be
969 absent from a multicast group before unrecoverable data loss will
970 occur.
971 Caution
973 Exercise care when setting large recovery intervals as the data
974 needed for recovery will be held in memory. For example, a 1 minute
975 recovery interval at a data rate of 1Gbps requires a 7GB in-memory
976 buffer.
977 Option value type int
980 Option value unit milliseconds
982 Default value 10000
984 Applicable socket types all, when using multicast
986 transports
987 ZMQ_REQ_CORRELATE: match replies with requests
990 The default behaviour of REQ sockets is to rely on the ordering of
991 messages to match requests and responses and that is usually
992 sufficient. When this option is set to 1, the REQ socket will prefix
993 outgoing messages with an extra frame containing a request id. That
994 means the full message is (request id, 0, user frames...). The REQ
995 socket will discard all incoming messages that don’t begin with these
996 two frames.
997 Option value type int
1000 Option value unit 0, 1
1003 Default value 0
1005 Applicable socket types ZMQ_REQ
1007 ZMQ_REQ_RELAXED: relax strict alternation between request and reply
1010 By default, a REQ socket does not allow initiating a new request with
1011 zmq_send(3) until the reply to the previous one has been received. When
1012 set to 1, sending another message is allowed and previous replies will
1013 be discarded if any. The request-reply state machine is reset and a new
1014 request is sent to the next available peer.
1015 If set to 1, also enable ZMQ_REQ_CORRELATE to ensure correct matching
1017 of requests and replies. Otherwise a late reply to an aborted request
1018 can be reported as the reply to the superseding request.
1019 Option value type int
1022 Option value unit 0, 1
1024 Default value 0
1026 Applicable socket types ZMQ_REQ
1028 ZMQ_ROUTER_HANDOVER: handle duplicate client routing ids on ROUTER sockets
1031 If two clients use the same routing id when connecting to a ROUTER, the
1032 results shall depend on the ZMQ_ROUTER_HANDOVER option setting. If that
1033 is not set (or set to the default of zero), the ROUTER socket shall
1034 reject clients trying to connect with an already-used routing id. If
1035 that option is set to 1, the ROUTER socket shall hand-over the
1036 connection to the new client and disconnect the existing one.
1037 Option value type int
1040 Option value unit 0, 1
1042 Default value 0
1044 Applicable socket types ZMQ_ROUTER
1046 ZMQ_ROUTER_MANDATORY: accept only routable messages on ROUTER sockets
1049 Sets the ROUTER socket behaviour when an unroutable message is
1050 encountered. A value of 0 is the default and discards the message
1051 silently when it cannot be routed or the peers SNDHWM is reached. A
1052 value of 1 returns an EHOSTUNREACH error code if the message cannot be
1053 routed or EAGAIN error code if the SNDHWM is reached and ZMQ_DONTWAIT
1054 was used. Without ZMQ_DONTWAIT it will block until the SNDTIMEO is
1055 reached or a spot in the send queue opens up.
1056 When ZMQ_ROUTER_MANDATORY is set to 1, ZMQ_POLLOUT events will be
1058 generated if one or more messages can be sent to at least one of the
1059 peers. If ZMQ_ROUTER_MANDATORY is set to 0, the socket will generate a
1060 ZMQ_POLLOUT event on every call to zmq_poll resp. zmq_poller_wait_all.
1061 Option value type int
1064 Option value unit 0, 1
1066 Default value 0
1070 Applicable socket types ZMQ_ROUTER
1072 ZMQ_ROUTER_RAW: switch ROUTER socket to raw mode
1075 Sets the raw mode on the ROUTER, when set to 1. When the ROUTER socket
1076 is in raw mode, and when using the tcp:// transport, it will read and
1077 write TCP data without 0MQ framing. This lets 0MQ applications talk to
1078 non-0MQ applications. When using raw mode, you cannot set explicit
1079 identities, and the ZMQ_SNDMORE flag is ignored when sending data
1080 messages. In raw mode you can close a specific connection by sending it
1081 a zero-length message (following the routing id frame).
1082 Note
1084 This option is deprecated, please use ZMQ_STREAM sockets instead.
1085 Option value type int
1088 Option value unit 0, 1
1090 Default value 0
1092 Applicable socket types ZMQ_ROUTER
1094 ZMQ_ROUTING_ID: Set socket routing id
1097 The ZMQ_ROUTING_ID option shall set the routing id of the specified
1098 socket when connecting to a ROUTER socket.
1099 A routing id must be at least one byte and at most 255 bytes long.
1101 Identities starting with a zero byte are reserved for use by the 0MQ
1102 infrastructure.
1103 If two clients use the same routing id when connecting to a ROUTER, the
1105 results shall depend on the ZMQ_ROUTER_HANDOVER option setting. If that
1106 is not set (or set to the default of zero), the ROUTER socket shall
1107 reject clients trying to connect with an already-used routing id. If
1108 that option is set to 1, the ROUTER socket shall hand-over the
1109 connection to the new client and disconnect the existing one.
1110 Option value type binary data
1113 Option value unit N/A
1115 Default value NULL
1117 Applicable socket types ZMQ_REQ, ZMQ_REP,
1119 ZMQ_ROUTER, ZMQ_DEALER.
1120 ZMQ_SNDBUF: Set kernel transmit buffer size
1123 The ZMQ_SNDBUF option shall set the underlying kernel transmit buffer
1124 size for the socket to the specified size in bytes. A value of -1 means
1125 leave the OS default unchanged. For details please refer to your
1126 operating system documentation for the SO_SNDBUF socket option.
1127 Option value type int
1130 Option value unit bytes
1132 Default value -1
1134 Applicable socket types all
1137 ZMQ_SNDHWM: Set high water mark for outbound messages
1140 The ZMQ_SNDHWM option shall set the high water mark for outbound
1141 messages on the specified socket. The high water mark is a hard limit
1142 on the maximum number of outstanding messages 0MQ shall queue in memory
1143 for any single peer that the specified socket is communicating with. A
1144 value of zero means no limit.
1145 If this limit has been reached the socket shall enter an exceptional
1147 state and depending on the socket type, 0MQ shall take appropriate
1148 action such as blocking or dropping sent messages. Refer to the
1149 individual socket descriptions in zmq_socket(3) for details on the
1150 exact action taken for each socket type.
1151 Note
1153 0MQ does not guarantee that the socket will accept as many as
1154 ZMQ_SNDHWM messages, and the actual limit may be as much as 90%
1155 lower depending on the flow of messages on the socket. The socket
1156 may even be able to accept more messages than the ZMQ_SNDHWM
1157 threshold; a notable example is for sockets using TCP transport;
1158 see zmq_tcp(7).
1159 Option value type int
1162 Option value unit messages
1164 Default value 1000
1166 Applicable socket types all
1168 ZMQ_SNDTIMEO: Maximum time before a send operation returns with EAGAIN
1171 Sets the timeout for send operation on the socket. If the value is 0,
1172 zmq_send(3) will return immediately, with a EAGAIN error if the message
1173 cannot be sent. If the value is -1, it will block until the message is
1174 sent. For all other values, it will try to send the message for that
1175 amount of time before returning with an EAGAIN error.
1176 Option value type int
1179 Option value unit milliseconds
1181 Default value -1 (infinite)
1183 Applicable socket types all
1185 ZMQ_SOCKS_PROXY: Set SOCKS5 proxy address
1188 Sets the SOCKS5 proxy address that shall be used by the socket for the
1189 TCP connection(s). Supported authentication methods are: no
1190 authentication or basic authentication when setup with
1191 ZMQ_SOCKS_USERNAME. If the endpoints are domain names instead of
1192 addresses they shall not be resolved and they shall be forwarded
1193 unchanged to the SOCKS proxy service in the client connection request
1194 message (address type 0x03 domain name).
1195 Option value type character string
1198 Option value unit N/A
1200 Default value not set
1204 Applicable socket types all, when using TCP
1206 transport
1207 ZMQ_SOCKS_USERNAME: Set SOCKS username and select basic authentication
1210 Sets the username for authenticated connection to the SOCKS5 proxy. If
1211 you set this to a non-null and non-empty value, the authentication
1212 method used for the SOCKS5 connection shall be basic authentication. In
1213 this case, use ZMQ_SOCKS_PASSWORD option in order to set the password.
1214 If you set this to a null value or empty value, the authentication
1215 method shall be no authentication, the default.
1216 Option value type character string
1219 Option value unit N/A
1221 Default value not set
1223 Applicable socket types all, when using TCP
1225 transport
1226 ZMQ_SOCKS_PASSWORD: Set SOCKS basic authentication password
1229 Sets the password for authenticating to the SOCKS5 proxy server. This
1230 is used only when the SOCKS5 authentication method has been set to
1231 basic authentication through the ZMQ_SOCKS_USERNAME option. Setting
1232 this to a null value (the default) is equivalent to an empty password
1233 string.
1234 Option value type character string
1237 Option value unit N/A
1239 Default value not set
1241 Applicable socket types all, when using TCP
1243 transport
1244 ZMQ_STREAM_NOTIFY: send connect and disconnect notifications
1247 Enables connect and disconnect notifications on a STREAM socket, when
1248 set to 1. When notifications are enabled, the socket delivers a
1249 zero-length message when a peer connects or disconnects.
1250 Option value type int
1253 Option value unit 0, 1
1255 Default value 1
1257 Applicable socket types ZMQ_STREAM
1259 ZMQ_SUBSCRIBE: Establish message filter
1262 The ZMQ_SUBSCRIBE option shall establish a new message filter on a
1263 ZMQ_SUB socket. Newly created ZMQ_SUB sockets shall filter out all
1264 incoming messages, therefore you should call this option to establish
1265 an initial message filter.
1266 An empty option_value of length zero shall subscribe to all incoming
1268 messages. A non-empty option_value shall subscribe to all messages
1269 beginning with the specified prefix. Multiple filters may be attached
1270 to a single ZMQ_SUB socket, in which case a message shall be accepted
1271 if it matches at least one filter.
1272 Option value type binary data
1275 Option value unit N/A
1277 Default value N/A
1279 Applicable socket types ZMQ_SUB
1281 ZMQ_TCP_KEEPALIVE: Override SO_KEEPALIVE socket option
1284 Override SO_KEEPALIVE socket option (where supported by OS). The
1285 default value of -1 means to skip any overrides and leave it to OS
1286 default.
1287 Option value type int
1290 Option value unit -1,0,1
1292 Default value -1 (leave to OS default)
1294 Applicable socket types all, when using TCP
1296 transports.
1297 ZMQ_TCP_KEEPALIVE_CNT: Override TCP_KEEPCNT socket option
1300 Override TCP_KEEPCNT socket option (where supported by OS). The default
1301 value of -1 means to skip any overrides and leave it to OS default.
1302 Option value type int
1305 Option value unit -1,>0
1307 Default value -1 (leave to OS default)
1309 Applicable socket types all, when using TCP
1311 transports.
1312 ZMQ_TCP_KEEPALIVE_IDLE: Override TCP_KEEPIDLE (or TCP_KEEPALIVE on some OS)
1315 Override TCP_KEEPIDLE (or TCP_KEEPALIVE on some OS) socket option
1316 (where supported by OS). The default value of -1 means to skip any
1317 overrides and leave it to OS default.
1318 Option value type int
1321 Option value unit -1,>0
1323 Default value -1 (leave to OS default)
1325 Applicable socket types all, when using TCP
1327 transports.
1328 ZMQ_TCP_KEEPALIVE_INTVL: Override TCP_KEEPINTVL socket option
1331 Override TCP_KEEPINTVL socket option(where supported by OS). The
1332 default value of -1 means to skip any overrides and leave it to OS
1333 default.
1334 Option value type int
1338 Option value unit -1,>0
1340 Default value -1 (leave to OS default)
1342 Applicable socket types all, when using TCP
1344 transports.
1345 ZMQ_TCP_MAXRT: Set TCP Maximum Retransmit Timeout
1348 On OSes where it is supported, sets how long before an unacknowledged
1349 TCP retransmit times out. The system normally attempts many TCP
1350 retransmits following an exponential backoff strategy. This means that
1351 after a network outage, it may take a long time before the session can
1352 be re-established. Setting this option allows the timeout to happen at
1353 a shorter interval.
1354 Option value type int
1357 Option value unit milliseconds
1359 Default value 0 (leave to OS default)
1361 Applicable socket types all, when using TCP
1363 transports.
1364 ZMQ_TOS: Set the Type-of-Service on socket
1367 Sets the ToS fields (Differentiated services (DS) and Explicit
1368 Congestion Notification (ECN) field of the IP header. The ToS field is
1369 typically used to specify a packets priority. The availability of this
1370 option is dependent on intermediate network equipment that inspect the
1371 ToS field and provide a path for low-delay, high-throughput,
1372 highly-reliable service, etc.
1373 Option value type int
1376 Option value unit >0
1378 Default value 0
1380 Applicable socket types all, only for
1382 connection-oriented
1383 transports
1384 ZMQ_UNSUBSCRIBE: Remove message filter
1387 The ZMQ_UNSUBSCRIBE option shall remove an existing message filter on a
1388 ZMQ_SUB socket. The filter specified must match an existing filter
1389 previously established with the ZMQ_SUBSCRIBE option. If the socket has
1390 several instances of the same filter attached the ZMQ_UNSUBSCRIBE
1391 option shall remove only one instance, leaving the rest in place and
1392 functional.
1393 Option value type binary data
1396 Option value unit N/A
1398 Default value N/A
1400 Applicable socket types ZMQ_SUB
1402 ZMQ_XPUB_VERBOSE: pass duplicate subscribe messages on XPUB socket
1405 Sets the XPUB socket behaviour on new duplicated subscriptions. If
1406 enabled, the socket passes all subscribe messages to the caller. If
1407 disabled, only the first subscription to each filter will be passed.
1408 The default is 0 (disabled).
1409 Option value type int
1412 Option value unit 0, 1
1414 Default value 0
1416 Applicable socket types ZMQ_XPUB
1418 ZMQ_XPUB_VERBOSER: pass duplicate subscribe and unsubscribe messages on
1421 XPUB socket
1422 Sets the XPUB socket behaviour on new duplicated subscriptions and
1423 unsubscriptions. If enabled, the socket passes all subscribe and
1424 unsubscribe messages to the caller. If disabled, only the first
1425 subscription to each filter and the last unsubscription from each
1426 filter will be passed. The default is 0 (disabled).
1427 Option value type int
1430 Option value unit 0, 1
1432 Default value 0
1434 Applicable socket types ZMQ_XPUB
1436 ZMQ_XPUB_MANUAL: change the subscription handling to manual
1439 Sets the XPUB socket subscription handling mode manual/automatic. A
1440 value of 0 is the default and subscription requests will be handled
1441 automatically. A value of 1 will change the subscription requests
1442 handling to manual, with manual mode subscription requests are not
1443 added to the subscription list. To add subscription the user need to
1444 call setsockopt with ZMQ_SUBSCRIBE on XPUB socket.
1445 Option value type int
1448 Option value unit 0, 1
1450 Default value 0
1452 Applicable socket types ZMQ_XPUB
1454 ZMQ_XPUB_MANUAL_LAST_VALUE: change the subscription handling to manual
1457 This option is similar to ZMQ_XPUB_MANUAL. The difference is that
1458 ZMQ_XPUB_MANUAL_LAST_VALUE changes the XPUB socket behaviour to send
1459 the first message to the last subscriber after the socket receives a
1460 subscription and call setsockopt with ZMQ_SUBSCRIBE on XPUB socket.
1461 This prevents duplicated messages when using last value caching(LVC).
1462 Note
1464 in DRAFT state, not yet available in stable releases.
1465 Option value type int
1468 Option value unit 0, 1
1472 Default value 0
1474 Applicable socket types ZMQ_XPUB
1476 ZMQ_XPUB_NODROP: do not silently drop messages if SENDHWM is reached
1479 Sets the XPUB socket behaviour to return error EAGAIN if SENDHWM is
1480 reached and the message could not be send.
1481 A value of 0 is the default and drops the message silently when the
1483 peers SNDHWM is reached. A value of 1 returns an EAGAIN error code if
1484 the SNDHWM is reached and ZMQ_DONTWAIT was used.
1485 Option value type int
1488 Option value unit 0, 1
1490 Default value 0
1492 Applicable socket types ZMQ_XPUB, ZMQ_PUB
1494 ZMQ_XPUB_WELCOME_MSG: set welcome message that will be received by
1497 subscriber when connecting
1498 Sets a welcome message the will be recieved by subscriber when
1499 connecting. Subscriber must subscribe to the Welcome message before
1500 connecting. Welcome message will also be sent on reconnecting. For
1501 welcome message to work well user must poll on incoming subscription
1502 messages on the XPUB socket and handle them.
1503 Use NULL and length of zero to disable welcome message.
1505 Option value type binary data
1508 Option value unit N/A
1510 Default value NULL
1512 Applicable socket types ZMQ_XPUB
1514 ZMQ_ONLY_FIRST_SUBSCRIBE: Process only first subscribe/unsubscribe in a
1517 multipart message
1518 If set, only the first part of the multipart message is processed as a
1519 subscribe/unsubscribe message. The rest are forwarded as user data
1520 regardless of message contents.
1521 It not set (default), subscribe/unsubscribe messages in a multipart
1523 message are processed as such regardless of their number and order.
1524 Option value type int
1527 Option value unit boolean
1529 Default value 0 (false)
1531 Applicable socket types ZMQ_XSUB, ZMQ_XPUB
1533 ZMQ_ZAP_DOMAIN: Set RFC 27 authentication domain
1536 Sets the domain for ZAP (ZMQ RFC 27) authentication. A ZAP domain must
1537 be specified to enable authentication. When the ZAP domain is empty,
1538 which is the default, ZAP authentication is disabled. This is not
1539 compatible with previous versions of libzmq, so it can be controlled by
1540 ZMQ_ZAP_ENFORCE_DOMAIN which for now is disabled by default. See
1541 http://rfc.zeromq.org/spec:27 for more details.
1542 Option value type character string
1545 Option value unit N/A
1547 Default value empty
1549 Applicable socket types all, when using TCP
1551 transport
1552 ZMQ_ZAP_ENFORCE_DOMAIN: Set ZAP domain handling to strictly adhere the RFC
1555 The ZAP (ZMQ RFC 27) authentication protocol specifies that a domain
1556 must always be set. Older versions of libzmq did not follow the spec
1557 and allowed an empty domain to be set. This option can be used to
1558 enabled or disable the stricter, backward incompatible behaviour. For
1559 now it is disabled by default, but in a future version it will be
1560 enabled by default.
1561 Option value type int
1564 Option value unit 0, 1
1566 Default value 0
1568 Applicable socket types all, when using ZAP
1570 ZMQ_TCP_ACCEPT_FILTER: Assign filters to allow new TCP connections
1573 Assign an arbitrary number of filters that will be applied for each new
1574 TCP transport connection on a listening socket. If no filters are
1575 applied, then the TCP transport allows connections from any IP address.
1576 If at least one filter is applied then new connection source ip should
1577 be matched. To clear all filters call zmq_setsockopt(socket,
1578 ZMQ_TCP_ACCEPT_FILTER, NULL, 0). Filter is a null-terminated string
1579 with ipv6 or ipv4 CIDR.
1580 Note
1582 This option is deprecated, please use authentication via the ZAP
1583 API and IP address allowing / blocking.
1584 Option value type binary data
1587 Option value unit N/A
1589 Default value no filters (allow from
1591 all)
1592 Applicable socket types all listening sockets,
1594 when using TCP transports.
1595 ZMQ_IPC_FILTER_GID: Assign group ID filters to allow new IPC connections
1598 Assign an arbitrary number of filters that will be applied for each new
1599 IPC transport connection on a listening socket. If no IPC filters are
1600 applied, then the IPC transport allows connections from any process. If
1601 at least one UID, GID, or PID filter is applied then new connection
1602 credentials should be matched. To clear all GID filters call
1603 zmq_setsockopt(socket, ZMQ_IPC_FILTER_GID, NULL, 0).
1604 Note
1606 GID filters are only available on platforms supporting SO_PEERCRED
1607 or LOCAL_PEERCRED socket options (currently only Linux and later
1608 versions of OS X).
1609 Note
1611 This option is deprecated, please use authentication via the ZAP
1612 API and IPC allowing / blocking.
1613 Option value type gid_t
1616 Option value unit N/A
1618 Default value no filters (allow from
1620 all)
1621 Applicable socket types all listening sockets,
1623 when using IPC transports.
1624 ZMQ_IPC_FILTER_PID: Assign process ID filters to allow new IPC connections
1627 Assign an arbitrary number of filters that will be applied for each new
1628 IPC transport connection on a listening socket. If no IPC filters are
1629 applied, then the IPC transport allows connections from any process. If
1630 at least one UID, GID, or PID filter is applied then new connection
1631 credentials should be matched. To clear all PID filters call
1632 zmq_setsockopt(socket, ZMQ_IPC_FILTER_PID, NULL, 0).
1633 Note
1635 PID filters are only available on platforms supporting the
1636 SO_PEERCRED socket option (currently only Linux).
1637 Note
1639 This option is deprecated, please use authentication via the ZAP
1640 API and IPC allowing / blocking.
1641 Option value type pid_t
1644 Option value unit N/A
1646 Default value no filters (allow from
1648 all)
1649 Applicable socket types all listening sockets,
1651 when using IPC transports.
1652 ZMQ_IPC_FILTER_UID: Assign user ID filters to allow new IPC connections
1655 Assign an arbitrary number of filters that will be applied for each new
1656 IPC transport connection on a listening socket. If no IPC filters are
1657 applied, then the IPC transport allows connections from any process. If
1658 at least one UID, GID, or PID filter is applied then new connection
1659 credentials should be matched. To clear all UID filters call
1660 zmq_setsockopt(socket, ZMQ_IPC_FILTER_UID, NULL, 0).
1661 Note
1663 UID filters are only available on platforms supporting SO_PEERCRED
1664 or LOCAL_PEERCRED socket options (currently only Linux and later
1665 versions of OS X).
1666 Note
1668 This option is deprecated, please use authentication via the ZAP
1669 API and IPC allowing / blocking.
1670 Option value type uid_t
1673 Option value unit N/A
1676 Default value no filters (allow from
1678 all)
1679 Applicable socket types all listening sockets,
1681 when using IPC transports.
1682 ZMQ_IPV4ONLY: Use IPv4-only on socket
1685 Set the IPv4-only option for the socket. This option is deprecated.
1686 Please use the ZMQ_IPV6 option.
1687 Option value type int
1690 Option value unit boolean
1692 Default value 1 (true)
1694 Applicable socket types all, when using TCP
1696 transports.
1697 ZMQ_VMCI_BUFFER_SIZE: Set buffer size of the VMCI socket
1700 The ZMQ_VMCI_BUFFER_SIZE option shall set the size of the underlying
1701 buffer for the socket. Used during negotiation before the connection is
1702 established.
1703 Option value type uint64_t
1706 Option value unit bytes
1708 Default value 65546
1710 Applicable socket types all, when using VMCI
1712 transport
1713 ZMQ_VMCI_BUFFER_MIN_SIZE: Set min buffer size of the VMCI socket
1716 The ZMQ_VMCI_BUFFER_MIN_SIZE option shall set the min size of the
1717 underlying buffer for the socket. Used during negotiation before the
1718 connection is established.
1719 Option value type uint64_t
1722 Option value unit bytes
1724 Default value 128
1726 Applicable socket types all, when using VMCI
1728 transport
1729 ZMQ_VMCI_BUFFER_MAX_SIZE: Set max buffer size of the VMCI socket
1732 The ZMQ_VMCI_BUFFER_MAX_SIZE option shall set the max size of the
1733 underlying buffer for the socket. Used during negotiation before the
1734 connection is established.
1735 Option value type uint64_t
1738 Option value unit bytes
1740 Default value 262144
1744 Applicable socket types all, when using VMCI
1746 transport
1747 ZMQ_VMCI_CONNECT_TIMEOUT: Set connection timeout of the VMCI socket
1750 The ZMQ_VMCI_CONNECT_TIMEOUT option shall set connection timeout for
1751 the socket.
1752 Option value type int
1755 Option value unit milliseconds
1757 Default value -1
1759 Applicable socket types all, when using VMCI
1761 transport
1762 ZMQ_MULTICAST_LOOP: Control multicast local loopback
1765 For multicast UDP sender sockets this option sets whether the data sent
1766 should be looped back on local listening sockets.
1767 Option value type int
1770 Option value unit 0, 1
1772 Default value 1
1774 Applicable socket types ZMQ_RADIO, when using UDP
1776 multicast transport
1777 ZMQ_ROUTER_NOTIFY: Send connect and disconnect notifications
1780 Enable connect and disconnect notifications on a ROUTER socket. When
1781 enabled, the socket delivers a zero-length message (with routing-id as
1782 first frame) when a peer connects or disconnects. It’s possible to
1783 notify both events for a peer by OR-ing the flag values. This option
1784 only applies to stream oriented (tcp, ipc) transports.
1785 Note
1787 in DRAFT state, not yet available in stable releases.
1788 Option value type int
1791 Option value unit 0, ZMQ_NOTIFY_CONNECT,
1793 ZMQ_NOTIFY_DISCONNECT,
1794 ZMQ_NOTIFY_CONNECT |
1795 ZMQ_NOTIFY_DISCONNECT
1796 Default value 0
1798 Applicable socket types ZMQ_ROUTER
1800 ZMQ_IN_BATCH_SIZE: Maximal receive batch size
1803 Sets the maximal amount of messages that can be received in a single
1804 recv system call. WARNING: this option should almost never be changed.
1805 The default has been chosen to offer the best compromise between
1806 latency and throughtput. In the vast majority of cases, changing this
1807 option will result in worst result if not outright breakages.
1808 Cannot be zero.
1810 Note
1812 in DRAFT state, not yet available in stable releases.
1813 Option value type int
1816 Option value unit messages
1818 Default value 8192
1820 Applicable socket types All, when using TCP, IPC,
1822 PGM or NORM transport.
1823 ZMQ_OUT_BATCH_SIZE: Maximal send batch size
1826 Sets the maximal amount of messages that can be sent in a single send
1827 system call. WARNING: this option should almost never be changed. The
1828 default has been chosen to offer the best compromise between latency
1829 and throughtput. In the vast majority of cases, changing this option
1830 will result in worst result if not outright breakages.
1831 Cannot be zero.
1833 Note
1835 in DRAFT state, not yet available in stable releases.
1836 Option value type int
1839 Option value unit messages
1841 Default value 8192
1843 Applicable socket types All, when using TCP, IPC,
1845 PGM or NORM transport.
1846
1849 The zmq_setsockopt() function shall return zero if successful.
1850 Otherwise it shall return -1 and set errno to one of the values defined
1851 below.
1852
1854 EINVAL
1855 The requested option option_name is unknown, or the requested
1856 option_len or option_value is invalid.
1857 ETERM
1859 The 0MQ context associated with the specified socket was
1860 terminated.
1861 ENOTSOCK
1863 The provided socket was invalid.
1864 EINTR
1866 The operation was interrupted by delivery of a signal.
1867
1869 Subscribing to messages on a ZMQ_SUB socket.
1870 /* Subscribe to all messages */
1872 rc = zmq_setsockopt (socket, ZMQ_SUBSCRIBE, "", 0);
1873 assert (rc == 0);
1874 /* Subscribe to messages prefixed with "ANIMALS.CATS" */
1875 rc = zmq_setsockopt (socket, ZMQ_SUBSCRIBE, "ANIMALS.CATS", 12);
1876 Setting I/O thread affinity.
1878 int64_t affinity;
1880 /* Incoming connections on TCP port 5555 shall be handled by I/O thread 1 */
1881 affinity = 1;
1882 rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
1883 assert (rc);
1884 rc = zmq_bind (socket, "tcp://lo:5555");
1885 assert (rc);
1886 /* Incoming connections on TCP port 5556 shall be handled by I/O thread 2 */
1887 affinity = 2;
1888 rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
1889 assert (rc);
1890 rc = zmq_bind (socket, "tcp://lo:5556");
1891 assert (rc);
1892
1895 zmq_getsockopt(3) zmq_socket(3) zmq_plain(7) zmq_curve(7) zmq(7)
1896
1898 This page was written by the 0MQ community. To make a change please
1899 read the 0MQ Contribution Policy at
1900 http://www.zeromq.org/docs:contributing.
19010MQ 4.3.4 01/21/2023 ZMQ_SETSOCKOPT(3)