Provided by: libzmq3-dev_4.0.4+dfsg-2ubuntu0.1_amd64 bug

NAME

       zmq_setsockopt - set 0MQ socket options

SYNOPSIS

       int zmq_setsockopt (void *socket, int option_name, const void *option_value, size_t
       option_len);

       Caution: All options, with the exception of ZMQ_SUBSCRIBE, ZMQ_UNSUBSCRIBE, ZMQ_LINGER,
       ZMQ_ROUTER_MANDATORY, ZMQ_PROBE_ROUTER, ZMQ_XPUB_VERBOSE, ZMQ_REQ_CORRELATE, and
       ZMQ_REQ_RELAXED, only take effect for subsequent socket bind/connects.

       Specifically, security options take effect for subsequent bind/connect calls, and can be
       changed at any time to affect subsequent binds and/or connects.

DESCRIPTION

       The zmq_setsockopt() function shall set the option specified by the option_name argument
       to the value pointed to by the option_value argument for the 0MQ socket pointed to by the
       socket argument. The option_len argument is the size of the option value in bytes.

       The following socket options can be set with the zmq_setsockopt() function:

   ZMQ_SNDHWM: Set high water mark for outbound messages
       The ZMQ_SNDHWM option shall set the high water mark for outbound messages on the specified
       socket. The high water mark is a hard limit on the maximum number of outstanding messages
       0MQ shall queue in memory for any single peer that the specified socket is communicating
       with. A value of zero means no limit.

       If this limit has been reached the socket shall enter an exceptional state and depending
       on the socket type, 0MQ shall take appropriate action such as blocking or dropping sent
       messages. Refer to the individual socket descriptions in zmq_socket(3) for details on the
       exact action taken for each socket type.

           Note
           0MQ does not guarantee that the socket will accept as many as ZMQ_SNDHWM messages, and
           the actual limit may be as much as 60-70% lower depending on the flow of messages on
           the socket.

       Option value type         int

       Option value unit         messages

       Default value             1000

       Applicable socket types   all

   ZMQ_RCVHWM: Set high water mark for inbound messages
       The ZMQ_RCVHWM option shall set the high water mark for inbound messages on the specified
       socket. The high water mark is a hard limit on the maximum number of outstanding messages
       0MQ shall queue in memory for any single peer that the specified socket is communicating
       with. A value of zero means no limit.

       If this limit has been reached the socket shall enter an exceptional state and depending
       on the socket type, 0MQ shall take appropriate action such as blocking or dropping sent
       messages. Refer to the individual socket descriptions in zmq_socket(3) for details on the
       exact action taken for each socket type.

       Option value type         int

       Option value unit         messages

       Default value             1000

       Applicable socket types   all

   ZMQ_AFFINITY: Set I/O thread affinity
       The ZMQ_AFFINITY option shall set the I/O thread affinity for newly created connections on
       the specified socket.

       Affinity determines which threads from the 0MQ I/O thread pool associated with the
       socket’s context shall handle newly created connections. A value of zero specifies no
       affinity, meaning that work shall be distributed fairly among all 0MQ I/O threads in the
       thread pool. For non-zero values, the lowest bit corresponds to thread 1, second lowest
       bit to thread 2 and so on. For example, a value of 3 specifies that subsequent connections
       on socket shall be handled exclusively by I/O threads 1 and 2.

       See also zmq_init(3) for details on allocating the number of I/O threads for a specific
       context.

       Option value type         uint64_t

       Option value unit         N/A (bitmap)

       Default value             0

       Applicable socket types   N/A

   ZMQ_SUBSCRIBE: Establish message filter
       The ZMQ_SUBSCRIBE option shall establish a new message filter on a ZMQ_SUB socket. Newly
       created ZMQ_SUB sockets shall filter out all incoming messages, therefore you should call
       this option to establish an initial message filter.

       An empty option_value of length zero shall subscribe to all incoming messages. A non-empty
       option_value shall subscribe to all messages beginning with the specified prefix. Multiple
       filters may be attached to a single ZMQ_SUB socket, in which case a message shall be
       accepted if it matches at least one filter.

       Option value type         binary data

       Option value unit         N/A

       Default value             N/A

       Applicable socket types   ZMQ_SUB

   ZMQ_UNSUBSCRIBE: Remove message filter
       The ZMQ_UNSUBSCRIBE option shall remove an existing message filter on a ZMQ_SUB socket.
       The filter specified must match an existing filter previously established with the
       ZMQ_SUBSCRIBE option. If the socket has several instances of the same filter attached the
       ZMQ_UNSUBSCRIBE option shall remove only one instance, leaving the rest in place and
       functional.

       Option value type         binary data

       Option value unit         N/A

       Default value             N/A

       Applicable socket types   ZMQ_SUB

   ZMQ_IDENTITY: Set socket identity
       The ZMQ_IDENTITY option shall set the identity of the specified socket when connecting to
       a ROUTER socket. The identity should be from 1 to 255 bytes long and MAY NOT start with
       binary zero.

       If two clients use the same identity when connecting to a ROUTER, the ROUTER socket shall
       accept only the first such client and reject the others.

       Option value type         binary data

       Option value unit         N/A

       Default value             NULL

       Applicable socket types   ZMQ_REQ, ZMQ_REP, ZMQ_ROUTER,
                                 ZMQ_DEALER.

   ZMQ_RATE: Set multicast data rate
       The ZMQ_RATE option shall set the maximum send or receive data rate for multicast
       transports such as zmq_pgm(7) using the specified socket.

       Option value type         int

       Option value unit         kilobits per second

       Default value             100

       Applicable socket types   all, when using multicast
                                 transports

   ZMQ_RECOVERY_IVL: Set multicast recovery interval
       The ZMQ_RECOVERY_IVL option shall set the recovery interval for multicast transports using
       the specified socket. The recovery interval determines the maximum time in milliseconds
       that a receiver can be absent from a multicast group before unrecoverable data loss will
       occur.

           Caution
           Exercise care when setting large recovery intervals as the data needed for recovery
           will be held in memory. For example, a 1 minute recovery interval at a data rate of
           1Gbps requires a 7GB in-memory buffer.

       Option value type         int

       Option value unit         milliseconds

       Default value             10000

       Applicable socket types   all, when using multicast
                                 transports

   ZMQ_SNDBUF: Set kernel transmit buffer size
       The ZMQ_SNDBUF option shall set the underlying kernel transmit buffer size for the socket
       to the specified size in bytes. A value of zero means leave the OS default unchanged. For
       details please refer to your operating system documentation for the SO_SNDBUF socket
       option.

       Option value type         int

       Option value unit         bytes

       Default value             0

       Applicable socket types   all

   ZMQ_RCVBUF: Set kernel receive buffer size
       The ZMQ_RCVBUF option shall set the underlying kernel receive buffer size for the socket
       to the specified size in bytes. A value of zero means leave the OS default unchanged. For
       details refer to your operating system documentation for the SO_RCVBUF socket option.

       Option value type         int

       Option value unit         bytes

       Default value             0

       Applicable socket types   all

   ZMQ_LINGER: Set linger period for socket shutdown
       The ZMQ_LINGER option shall set the linger period for the specified socket. The linger
       period determines how long pending messages which have yet to be sent to a peer shall
       linger in memory after a socket is closed with zmq_close(3), and further affects the
       termination of the socket’s context with zmq_term(3). The following outlines the different
       behaviours:

       •   The default value of -1 specifies an infinite linger period. Pending messages shall
           not be discarded after a call to zmq_close(); attempting to terminate the socket’s
           context with zmq_term() shall block until all pending messages have been sent to a
           peer.

       •   The value of 0 specifies no linger period. Pending messages shall be discarded
           immediately when the socket is closed with zmq_close().

       •   Positive values specify an upper bound for the linger period in milliseconds. Pending
           messages shall not be discarded after a call to zmq_close(); attempting to terminate
           the socket’s context with zmq_term() shall block until either all pending messages
           have been sent to a peer, or the linger period expires, after which any pending
           messages shall be discarded.

           Option value type         int
           Option value unit         milliseconds
           Default value             -1 (infinite)
           Applicable socket types   all

   ZMQ_RECONNECT_IVL: Set reconnection interval
       The ZMQ_RECONNECT_IVL option shall set the initial reconnection interval for the specified
       socket. The reconnection interval is the period 0MQ shall wait between attempts to
       reconnect disconnected peers when using connection-oriented transports. The value -1 means
       no reconnection.

           Note
           The reconnection interval may be randomized by 0MQ to prevent reconnection storms in
           topologies with a large number of peers per socket.

       Option value type         int

       Option value unit         milliseconds

       Default value             100

       Applicable socket types   all, only for
                                 connection-oriented transports

   ZMQ_RECONNECT_IVL_MAX: Set maximum reconnection interval
       The ZMQ_RECONNECT_IVL_MAX option shall set the maximum reconnection interval for the
       specified socket. This is the maximum period 0MQ shall wait between attempts to reconnect.
       On each reconnect attempt, the previous interval shall be doubled untill
       ZMQ_RECONNECT_IVL_MAX is reached. This allows for exponential backoff strategy. Default
       value means no exponential backoff is performed and reconnect interval calculations are
       only based on ZMQ_RECONNECT_IVL.

           Note
           Values less than ZMQ_RECONNECT_IVL will be ignored.

       Option value type         int

       Option value unit         milliseconds

       Default value             0 (only use ZMQ_RECONNECT_IVL)

       Applicable socket types   all, only for
                                 connection-oriented transports

   ZMQ_BACKLOG: Set maximum length of the queue of outstanding connections
       The ZMQ_BACKLOG option shall set the maximum length of the queue of outstanding peer
       connections for the specified socket; this only applies to connection-oriented transports.
       For details refer to your operating system documentation for the listen function.

       Option value type         int

       Option value unit         connections

       Default value             100

       Applicable socket types   all, only for
                                 connection-oriented transports.

   ZMQ_MAXMSGSIZE: Maximum acceptable inbound message size
       Limits the size of the inbound message. If a peer sends a message larger than
       ZMQ_MAXMSGSIZE it is disconnected. Value of -1 means no limit.

       Option value type         int64_t

       Option value unit         bytes

       Default value             -1

       Applicable socket types   all

   ZMQ_MULTICAST_HOPS: Maximum network hops for multicast packets
       Sets the time-to-live field in every multicast packet sent from this socket. The default
       is 1 which means that the multicast packets don’t leave the local network.

       Option value type         int

       Option value unit         network hops

       Default value             1

       Applicable socket types   all, when using multicast
                                 transports

   ZMQ_RCVTIMEO: Maximum time before a recv operation returns with EAGAIN
       Sets the timeout for receive operation on the socket. If the value is 0, zmq_recv(3) will
       return immediately, with a EAGAIN error if there is no message to receive. If the value is
       -1, it will block until a message is available. For all other values, it will wait for a
       message for that amount of time before returning with an EAGAIN error.

       Option value type         int

       Option value unit         milliseconds

       Default value             -1 (infinite)

       Applicable socket types   all

   ZMQ_SNDTIMEO: Maximum time before a send operation returns with EAGAIN
       Sets the timeout for send operation on the socket. If the value is 0, zmq_send(3) will
       return immediately, with a EAGAIN error if the message cannot be sent. If the value is -1,
       it will block until the message is sent. For all other values, it will try to send the
       message for that amount of time before returning with an EAGAIN error.

       Option value type         int

       Option value unit         milliseconds

       Default value             -1 (infinite)

       Applicable socket types   all

   ZMQ_IPV6: Enable IPv6 on socket
       Set the IPv6 option for the socket. A value of 1 means IPv6 is enabled on the socket,
       while 0 means the socket will use only IPv4. When IPv6 is enabled the socket will connect
       to, or accept connections from, both IPv4 and IPv6 hosts.

       Option value type         int

       Option value unit         boolean

       Default value             0 (false)

       Applicable socket types   all, when using TCP transports.

   ZMQ_IPV4ONLY: Use IPv4-only on socket
       Set the IPv4-only option for the socket. This option is deprecated. Please use the
       ZMQ_IPV6 option.

       Option value type         int

       Option value unit         boolean

       Default value             1 (true)

       Applicable socket types   all, when using TCP transports.

   ZMQ_IMMEDIATE: Queue messages only to completed connections
       By default queues will fill on outgoing connections even if the connection has not
       completed. This can lead to "lost" messages on sockets with round-robin routing (REQ,
       PUSH, DEALER). If this option is set to 1, messages shall be queued only to completed
       connections. This will cause the socket to block if there are no other connections, but
       will prevent queues from filling on pipes awaiting connection.

       Option value type         int

       Option value unit         boolean

       Default value             0 (false)

       Applicable socket types   all, only for
                                 connection-oriented transports.

   ZMQ_ROUTER_MANDATORY: accept only routable messages on ROUTER sockets
       Sets the ROUTER socket behavior when an unroutable message is encountered. A value of 0 is
       the default and discards the message silently when it cannot be routed. A value of 1
       returns an EHOSTUNREACH error code if the message cannot be routed.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_ROUTER

   ZMQ_ROUTER_RAW: switch ROUTER socket to raw mode
       Sets the raw mode on the ROUTER, when set to 1. When the ROUTER socket is in raw mode, and
       when using the tcp:// transport, it will read and write TCP data without 0MQ framing. This
       lets 0MQ applications talk to non-0MQ applications. When using raw mode, you cannot set
       explicit identities, and the ZMQ_MSGMORE flag is ignored when sending data messages. In
       raw mode you can close a specific connection by sending it a zero-length message
       (following the identity frame).

           Note
           This option is deprecated, please use ZMQ_STREAM sockets instead.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_ROUTER

   ZMQ_PROBE_ROUTER: bootstrap connections to ROUTER sockets
       When set to 1, the socket will automatically send an empty message when a new connection
       is made or accepted. You may set this on REQ, DEALER, or ROUTER sockets connected to a
       ROUTER socket. The application must filter such empty messages. The ZMQ_PROBE_ROUTER
       option in effect provides the ROUTER application with an event signaling the arrival of a
       new peer.

           Note
           do not set this option on a socket that talks to any other socket types: the results
           are undefined.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_ROUTER, ZMQ_DEALER, ZMQ_REQ

   ZMQ_XPUB_VERBOSE: provide all subscription messages on XPUB sockets
       Sets the XPUB socket behavior on new subscriptions and unsubscriptions. A value of 0 is
       the default and passes only new subscription messages to upstream. A value of 1 passes all
       subscription messages upstream.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_XPUB

   ZMQ_REQ_CORRELATE: match replies with requests
       The default behavior of REQ sockets is to rely on the ordering of messages to match
       requests and responses and that is usually sufficient. When this option is set to 1, the
       REQ socket will prefix outgoing messages with an extra frame containing a request id. That
       means the full message is (request id, 0, user frames...). The REQ socket will discard all
       incoming messages that don’t begin with these two frames.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_REQ

   ZMQ_REQ_RELAXED: relax strict alternation between request and reply
       By default, a REQ socket does not allow initiating a new request with zmq_send(3) until
       the reply to the previous one has been received. When set to 1, sending another message is
       allowed and has the effect of disconnecting the underlying connection to the peer from
       which the reply was expected, triggering a reconnection attempt on transports that support
       it. The request-reply state machine is reset and a new request is sent to the next
       available peer.

       If set to 1, also enable ZMQ_REQ_CORRELATE to ensure correct matching of requests and
       replies. Otherwise a late reply to an aborted request can be reported as the reply to the
       superseding request.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   ZMQ_REQ

   ZMQ_TCP_KEEPALIVE: Override SO_KEEPALIVE socket option
       Override SO_KEEPALIVE socket option (where supported by OS). The default value of -1 means
       to skip any overrides and leave it to OS default.

       Option value type         int

       Option value unit         -1,0,1

       Default value             -1 (leave to OS default)

       Applicable socket types   all, when using TCP transports.

   ZMQ_TCP_KEEPALIVE_IDLE: Override TCP_KEEPCNT (or TCP_KEEPALIVE on some OS)
       Override TCP_KEEPCNT(or TCP_KEEPALIVE on some OS) socket option (where supported by OS).
       The default value of -1 means to skip any overrides and leave it to OS default.

       Option value type         int

       Option value unit         -1,>0

       Default value             -1 (leave to OS default)

       Applicable socket types   all, when using TCP transports.

   ZMQ_TCP_KEEPALIVE_CNT: Override TCP_KEEPCNT socket option
       Override TCP_KEEPCNT socket option (where supported by OS). The default value of -1 means
       to skip any overrides and leave it to OS default.

       Option value type         int

       Option value unit         -1,>0

       Default value             -1 (leave to OS default)

       Applicable socket types   all, when using TCP transports.

   ZMQ_TCP_KEEPALIVE_INTVL: Override TCP_KEEPINTVL socket option
       Override TCP_KEEPINTVL socket option(where supported by OS). The default value of -1 means
       to skip any overrides and leave it to OS default.

       Option value type         int

       Option value unit         -1,>0

       Default value             -1 (leave to OS default)

       Applicable socket types   all, when using TCP transports.

   ZMQ_TCP_ACCEPT_FILTER: Assign filters to allow new TCP connections
       Assign an arbitrary number of filters that will be applied for each new TCP transport
       connection on a listening socket. If no filters are applied, then the TCP transport allows
       connections from any IP address. If at least one filter is applied then new connection
       source ip should be matched. To clear all filters call zmq_setsockopt(socket,
       ZMQ_TCP_ACCEPT_FILTER, NULL, 0). Filter is a null-terminated string with ipv6 or ipv4
       CIDR.

       Option value type         binary data

       Option value unit         N/A

       Default value             no filters (allow from all)

       Applicable socket types   all listening sockets, when
                                 using TCP transports.

   ZMQ_PLAIN_SERVER: Set PLAIN server role
       Defines whether the socket will act as server for PLAIN security, see zmq_plain(7). A
       value of 1 means the socket will act as PLAIN server. A value of 0 means the socket will
       not act as PLAIN server, and its security role then depends on other option settings.
       Setting this to 0 shall reset the socket security to NULL.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   all, when using TCP transport

   ZMQ_PLAIN_USERNAME: Set PLAIN security username
       Sets the username for outgoing connections over TCP or IPC. If you set this to a non-null
       value, the security mechanism used for connections shall be PLAIN, see zmq_plain(7). If
       you set this to a null value, the security mechanism used for connections shall be NULL,
       see zmq_null(3).

       Option value type         character string

       Option value unit         N/A

       Default value             not set

       Applicable socket types   all, when using TCP transport

   ZMQ_PLAIN_PASSWORD: Set PLAIN security password
       Sets the password for outgoing connections over TCP or IPC. If you set this to a non-null
       value, the security mechanism used for connections shall be PLAIN, see zmq_plain(7). If
       you set this to a null value, the security mechanism used for connections shall be NULL,
       see zmq_null(3).

       Option value type         character string

       Option value unit         N/A

       Default value             not set

       Applicable socket types   all, when using TCP transport

   ZMQ_CURVE_SERVER: Set CURVE server role
       Defines whether the socket will act as server for CURVE security, see zmq_curve(7). A
       value of 1 means the socket will act as CURVE server. A value of 0 means the socket will
       not act as CURVE server, and its security role then depends on other option settings.
       Setting this to 0 shall reset the socket security to NULL. When you set this you must also
       set the server’s secret key using the ZMQ_CURVE_SECRETKEY option. A server socket does not
       need to know its own public key.

       Option value type         int

       Option value unit         0, 1

       Default value             0

       Applicable socket types   all, when using TCP transport

   ZMQ_CURVE_PUBLICKEY: Set CURVE public key
       Sets the socket’s long term public key. You must set this on CURVE client sockets, see
       zmq_curve(7). You can provide the key as 32 binary bytes, or as a 40-character string
       encoded in the Z85 encoding format. The public key must always be used with the matching
       secret key. To generate a public/secret key pair, use zmq_curve_keypair(3).

       Option value type         binary data or Z85 text string

       Option value size         32 or 40

       Default value             NULL

       Applicable socket types   all, when using TCP transport

   ZMQ_CURVE_SECRETKEY: Set CURVE secret key
       Sets the socket’s long term secret key. You must set this on both CURVE client and server
       sockets, see zmq_curve(7). You can provide the key as 32 binary bytes, or as a
       40-character string encoded in the Z85 encoding format. To generate a public/secret key
       pair, use zmq_curve_keypair(3).

       Option value type         binary data or Z85 text string

       Option value size         32 or 40

       Default value             NULL

       Applicable socket types   all, when using TCP transport

   ZMQ_CURVE_SERVERKEY: Set CURVE server key
       Sets the socket’s long term server key. You must set this on CURVE client sockets, see
       zmq_curve(7). You can provide the key as 32 binary bytes, or as a 40-character string
       encoded in the Z85 encoding format. This key must have been generated together with the
       server’s secret key.

       Option value type         binary data or Z85 text string

       Option value size         32 or 40

       Default value             NULL

       Applicable socket types   all, when using TCP transport

   ZMQ_ZAP_DOMAIN: Set RFC 27 authentication domain
       Sets the domain for ZAP (ZMQ RFC 27) authentication. For NULL security (the default on all
       tcp:// connections), ZAP authentication only happens if you set a non-empty domain. For
       PLAIN and CURVE security, ZAP requests are always made, if there is a ZAP handler present.
       See http://rfc.zeromq.org/spec:27 for more details.

       Option value type         character string

       Option value unit         N/A

       Default value             not set

       Applicable socket types   all, when using TCP transport

   ZMQ_CONFLATE: Keep only last message
       If set, a socket shall keep only one message in its inbound/outbound queue, this message
       being the last message received/the last message to be sent. Ignores ZMQ_RECVHWM and
       ZMQ_SENDHWM options. Does not supports multi-part messages, in particular, only one part
       of it is kept in the socket internal queue.

       Option value type         int

       Option value unit         boolean

       Default value             0 (false)

       Applicable socket types   ZMQ_PULL, ZMQ_PUSH, ZMQ_SUB,
                                 ZMQ_PUB, ZMQ_DEALER

RETURN VALUE

       The zmq_setsockopt() function shall return zero if successful. Otherwise it shall return
       -1 and set errno to one of the values defined below.

ERRORS

       EINVAL
           The requested option option_name is unknown, or the requested option_len or
           option_value is invalid.

       ETERM
           The 0MQ context associated with the specified socket was terminated.

       ENOTSOCK
           The provided socket was invalid.

       EINTR
           The operation was interrupted by delivery of a signal.

EXAMPLE

       Subscribing to messages on a ZMQ_SUB socket.

           /* Subscribe to all messages */
           rc = zmq_setsockopt (socket, ZMQ_SUBSCRIBE, "", 0);
           assert (rc == 0);
           /* Subscribe to messages prefixed with "ANIMALS.CATS" */
           rc = zmq_setsockopt (socket, ZMQ_SUBSCRIBE, "ANIMALS.CATS", 12);

       Setting I/O thread affinity.

           int64_t affinity;
           /* Incoming connections on TCP port 5555 shall be handled by I/O thread 1 */
           affinity = 1;
           rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
           assert (rc);
           rc = zmq_bind (socket, "tcp://lo:5555");
           assert (rc);
           /* Incoming connections on TCP port 5556 shall be handled by I/O thread 2 */
           affinity = 2;
           rc = zmq_setsockopt (socket, ZMQ_AFFINITY, &affinity, sizeof (affinity));
           assert (rc);
           rc = zmq_bind (socket, "tcp://lo:5556");
           assert (rc);

SEE ALSO

       zmq_getsockopt(3) zmq_socket(3) zmq_plain(7) zmq_curve(7) zmq(7)

AUTHORS

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       Contribution Policy at http://www.zeromq.org/docs:contributing.