ZMQ_SETSOCKOPT
Section: 0MQ Manual (3)
Updated: 12/31/2016
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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_HANDOVER, ZMQ_ROUTER_MANDATORY, ZMQ_PROBE_ROUTER, ZMQ_XPUB_VERBOSE, ZMQ_XPUB_VERBOSER, ZMQ_REQ_CORRELATE, ZMQ_REQ_RELAXED, ZMQ_SNDHWM and ZMQ_RCVHWM, 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. For options taking a value of type "character string", the provided byte data should either contain no zero bytes, or end in a single zero byte (terminating ASCII NUL character).
The following socket options can be set with the zmq_setsockopt() function:
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 socketcqs 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_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_CONNECT_RID: Assign the next outbound connection id
The ZMQ_CONNECT_RID option sets the peer id of the next host connected via the zmq_connect() call, and immediately readies that connection for data transfer with the named id. This option applies only to the first subsequent call to zmq_connect(), calls thereafter use default connection behaviour.
Typical use is to set this socket option ahead of each zmq_connect() attempt to a new host. Each connection MUST be assigned a unique name. Assigning a name that is already in use is not allowed.
Useful when connecting ROUTER to ROUTER, or STREAM to STREAM, as it allows for immediate sending to peers. Outbound id framing requirements for ROUTER and STREAM sockets apply.
The peer id should be from 1 to 255 bytes long and MAY NOT start with binary zero.
|
Option value type
|
binary data
|
|
Option value unit
|
N/A
|
|
Default value
|
NULL
|
|
Applicable socket types
|
ZMQ_ROUTER, ZMQ_STREAM
|
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_RCVHWM and ZMQ_SNDHWM options. Does not support 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
|
ZMQ_CONNECT_TIMEOUT: Set connect() timeout
Sets how long to wait before timing-out a connect() system call. The connect() system call normally takes a long time before it returns a time out error. Setting this option allows the library to time out the call at an earlier interval.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
0 (disabled)
|
|
Applicable socket types
|
all, when using TCP transports.
|
ZMQ_CURVE_PUBLICKEY: Set CURVE public key
Sets the socketcqs 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 and terminated in a null byte. The public key must always be used with the matching secret key. To generate a public/secret key pair, use zmq_curve_keypair(3). To derive the public key from a secret key, use zmq_curve_public(3).
-
Note
an option value size of 40 is supported for backwards compatibility, though is deprecated.
|
Option value type
|
binary data or Z85 text string
|
|
Option value size
|
32 or 41
|
|
Default value
|
NULL
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_CURVE_SECRETKEY: Set CURVE secret key
Sets the socketcqs 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 and terminated in a null byte. To generate a public/secret key pair, use zmq_curve_keypair(3). To derive the public key from a secret key, use zmq_curve_public(3).
-
Note
an option value size of 40 is supported for backwards compatibility, though is deprecated.
|
Option value type
|
binary data or Z85 text string
|
|
Option value size
|
32 or 41
|
|
Default value
|
NULL
|
|
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 servercqs 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_SERVERKEY: Set CURVE server key
Sets the socketcqs 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 and terminated in a null byte. This key must have been generated together with the servercqs secret key. To generate a public/secret key pair, use zmq_curve_keypair(3).
-
Note
an option value size of 40 is supported for backwards compatibility, though is deprecated.
|
Option value type
|
binary data or Z85 text string
|
|
Option value size
|
32 or 41
|
|
Default value
|
NULL
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_GSSAPI_PLAINTEXT: Disable GSSAPI encryption
Defines whether communications on the socket will encrypted, see zmq_gssapi(7). A value of 1 means that communications will be plaintext. A value of 0 means communications will be encrypted.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0 (false)
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_GSSAPI_PRINCIPAL: Set name of GSSAPI principal
Sets the name of the principal for whom GSSAPI credentials should be acquired.
|
Option value type
|
character string
|
|
Option value unit
|
N/A
|
|
Default value
|
not set
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_GSSAPI_SERVER: Set GSSAPI server role
Defines whether the socket will act as server for GSSAPI security, see zmq_gssapi(7). A value of 1 means the socket will act as GSSAPI server. A value of 0 means the socket will act as GSSAPI client.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0 (false)
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_GSSAPI_SERVICE_PRINCIPAL: Set name of GSSAPI service principal
Sets the name of the principal of the GSSAPI server to which a GSSAPI client intends to connect.
|
Option value type
|
character string
|
|
Option value unit
|
N/A
|
|
Default value
|
not set
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_HANDSHAKE_IVL: Set maximum handshake interval
The ZMQ_HANDSHAKE_IVL option shall set the maximum handshake interval for the specified socket. Handshaking is the exchange of socket configuration information (socket type, identity, security) that occurs when a connection is first opened, only for connection-oriented transports. If handshaking does not complete within the configured time, the connection shall be closed. The value 0 means no handshake time limit.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
30000
|
|
Applicable socket types
|
all but ZMQ_STREAM, only for connection-oriented transports
|
ZMQ_HEARTBEAT_IVL: Set interval between sending ZMTP heartbeats
The ZMQ_HEARTBEAT_IVL option shall set the interval between sending ZMTP heartbeats for the specified socket. If this option is set and is greater than 0, then a PING ZMTP command will be sent every ZMQ_HEARTBEAT_IVL milliseconds.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
0
|
|
Applicable socket types
|
all, when using connection-oriented transports
|
ZMQ_HEARTBEAT_TIMEOUT: Set timeout for ZMTP heartbeats
The ZMQ_HEARTBEAT_TIMEOUT option shall set how long to wait before timing-out a connection after sending a PING ZMTP command and not receiving any traffic. This option is only valid if ZMQ_HEARTBEAT_IVL is also set, and is greater than 0. The connection will time out if there is no traffic received after sending the PING command, but the received traffic does not have to be a PONG command - any received traffic will cancel the timeout.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
0
|
|
Applicable socket types
|
all, when using connection-oriented transports
|
ZMQ_HEARTBEAT_TTL: Set the TTL value for ZMTP heartbeats
The ZMQ_HEARTBEAT_TTL option shall set the timeout on the remote peer for ZMTP heartbeats. If this option is greater than 0, the remote side shall time out the connection if it does not receive any more traffic within the TTL period. This option does not have any effect if ZMQ_HEARTBEAT_IVL is not set or is 0. Internally, this value is rounded down to the nearest decisecond, any value less than 100 will have no effect.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
0
|
|
Applicable socket types
|
all, when using connection-oriented transports
|
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 contain any values.
If two clients use the same identity when connecting to a ROUTER, the results shall depend on the ZMQ_ROUTER_HANDOVER option setting. If that is not set (or set to the default of zero), the ROUTER socket shall reject clients trying to connect with an already-used identity. If that option is set to 1, the ROUTER socket shall hand-over the connection to the new client and disconnect the existing one.
|
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_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_INVERT_MATCHING: Invert message filtering
Reverses the filtering behavior of PUB-SUB sockets, when set to 1.
On PUB and XPUB sockets, this causes messages to be sent to all connected sockets except those subscribed to a prefix that matches the message. On SUB sockets, this causes only incoming messages that do not match any of the socketcqs subscriptions to be received by the user.
Whenever ZMQ_INVERT_MATCHING is set to 1 on a PUB socket, all SUB sockets connecting to it must also have the option set to 1. Failure to do so will have the SUB sockets reject everything the PUB socket sends them. XSUB sockets do not need to do this because they do not filter incoming messages.
|
Option value type
|
int
|
|
Option value unit
|
0,1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_PUB, ZMQ_XPUB, ZMQ_SUB
|
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_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 disconnected with zmq_disconnect(3) or closed with zmq_close(3), and further affects the termination of the socketcqs context with zmq_ctx_term(3). The following outlines the different behaviours:
-
*
A value of
-1
specifies an infinite linger period. Pending messages shall not be discarded after a call to
zmq_disconnect()
or
zmq_close(); attempting to terminate the socketcqs context with
zmq_ctx_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 after a call to
zmq_disconnect()
or
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_disconnect()
or
zmq_close(); attempting to terminate the socketcqs context with
zmq_ctx_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
|
30000 (thirty seconds)
|
|
Applicable socket types
|
all
|
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 doncqt 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_MULTICAST_MAXTPDU: Maximum transport data unit size for multicast packets
Sets the maximum transport data unit size used for outbound multicast packets.
This must be set at or below the minimum Maximum Transmission Unit (MTU) for all network paths over which multicast reception is required.
|
Option value type
|
int
|
|
Option value unit
|
bytes
|
|
Default value
|
1500
|
|
Applicable socket types
|
all, when using multicast transports
|
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_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_USE_FD: Set the pre-allocated socket file descriptor
When set to a positive integer value before zmq_bind is called on the socket, the socket shall use the corresponding file descriptor for connections over TCP or IPC instead of allocating a new file descriptor. Useful for writing systemd socket activated services. If set to -1 (default), a new file descriptor will be allocated instead (default behaviour).
-
Note
if set after calling zmq_bind, this option shall have no effect. NOTE: the file descriptor passed through MUST have been ran through the "bind" and "listen" system calls beforehand. Also, socket option that would normally be passed through zmq_setsockopt like TCP buffers length, IP_TOS or SO_REUSEADDR MUST be set beforehand by the caller, as they must be set before the socket is bound.
|
Option value type
|
int
|
|
Option value unit
|
file descriptor
|
|
Default value
|
-1
|
|
Applicable socket types
|
all bound sockets, when using IPC or TCP transport
|
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_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_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 -1 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
|
-1
|
|
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_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_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_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_REQ_CORRELATE: match replies with requests
The default behaviour 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 doncqt 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 previous replies will be discarded if any. 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_ROUTER_HANDOVER: handle duplicate client identities on ROUTER sockets
If two clients use the same identity when connecting to a ROUTER, the results shall depend on the ZMQ_ROUTER_HANDOVER option setting. If that is not set (or set to the default of zero), the ROUTER socket shall reject clients trying to connect with an already-used identity. If that option is set to 1, the ROUTER socket shall hand-over the connection to the new client and disconnect the existing one.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_ROUTER
|
ZMQ_ROUTER_MANDATORY: accept only routable messages on ROUTER sockets
Sets the ROUTER socket behaviour when an unroutable message is encountered. A value of 0 is the default and discards the message silently when it cannot be routed or the peers SNDHWM is reached. A value of 1 returns an EHOSTUNREACH error code if the message cannot be routed or EAGAIN error code if the SNDHWM is reached and ZMQ_DONTWAIT was used. Without ZMQ_DONTWAIT it will block until the SNDTIMEO is reached or a spot in the send queue opens up.
|
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_SNDMORE 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_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 -1 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
|
-1
|
|
Applicable socket types
|
all
|
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_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_SOCKS_PROXY: Set SOCKS5 proxy address
Sets the SOCKS5 proxy address that shall be used by the socket for the TCP connection(s). Does not support SOCKS5 authentication. If the endpoints are domain names instead of addresses they shall not be resolved and they shall be forwarded unchanged to the SOCKS proxy service in the client connection request message (address type 0x03 domain name).
|
Option value type
|
character string
|
|
Option value unit
|
N/A
|
|
Default value
|
not set
|
|
Applicable socket types
|
all, when using TCP transport
|
ZMQ_STREAM_NOTIFY: send connect and disconnect notifications
Enables connect and disconnect notifications on a STREAM socket, when set to 1. When notifications are enabled, the socket delivers a zero-length message when a peer connects or disconnects.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
1
|
|
Applicable socket types
|
ZMQ_STREAM
|
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_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_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_IDLE: Override TCP_KEEPIDLE (or TCP_KEEPALIVE on some OS)
Override TCP_KEEPIDLE (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_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_MAXRT: Set TCP Maximum Retransmit Timeout
On OSes where it is supported, sets how long before an unacknowledged TCP retransmit times out. The system normally attempts many TCP retransmits following an exponential backoff strategy. This means that after a network outage, it may take a long time before the session can be re-established. Setting this option allows the timeout to happen at a shorter interval.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
0 (leave to OS default)
|
|
Applicable socket types
|
all, when using TCP transports.
|
ZMQ_TOS: Set the Type-of-Service on socket
Sets the ToS fields (Differentiated services (DS) and Explicit Congestion Notification (ECN) field of the IP header. The ToS field is typically used to specify a packets priority. The availability of this option is dependent on intermediate network equipment that inspect the ToS field and provide a path for low-delay, high-throughput, highly-reliable service, etc.
|
Option value type
|
int
|
|
Option value unit
|
>0
|
|
Default value
|
0
|
|
Applicable socket types
|
all, only for connection-oriented transports
|
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_XPUB_VERBOSE: pass subscribe messages on XPUB socket
Sets the XPUB socket behaviour on new subscriptions. If enabled, the socket passes all subscribe messages to the caller. If disabled, these are not visible to the caller. The default is 0 (disabled).
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_XPUB
|
ZMQ_XPUB_VERBOSER: pass subscribe and unsubscribe messages on XPUB socket
Sets the XPUB socket behaviour on new subscriptions and ubsubscriptions. If enabled, the socket passes all subscribe and unsubscribe messages to the caller. If disabled, these are not visible to the caller. The default is 0 (disabled).
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_XPUB
|
ZMQ_XPUB_MANUAL: change the subscription handling to manual
Sets the XPUB socket subscription handling mode manual/automatic. A value of 0 is the default and subscription requests will be handled automatically. A value of 1 will change the subscription requests handling to manual, with manual mode subscription requests are not added to the subscription list. To add subscription the user need to call setsockopt with ZMQ_SUBSCRIBE on XPUB socket.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_XPUB
|
ZMQ_XPUB_NODROP: do not silently drop messages if SENDHWM is reached
Sets the XPUB socket behaviour to return error EAGAIN if SENDHWM is reached and the message could not be send.
A value of 0 is the default and drops the message silently when the peers SNDHWM is reached. A value of 1 returns an EAGAIN error code if the SNDHWM is reached and ZMQ_DONTWAIT was used.
|
Option value type
|
int
|
|
Option value unit
|
0, 1
|
|
Default value
|
0
|
|
Applicable socket types
|
ZMQ_XPUB, ZMQ_PUB
|
ZMQ_XPUB_WELCOME_MSG: set welcome message that will be received by subscriber when connecting
Sets a welcome message the will be recieved by subscriber when connecting. Subscriber must subscribe to the Welcome message before connecting. Welcome message will also be sent on reconnecting. For welcome message to work well user must poll on incoming subscription messages on the XPUB socket and handle them.
Use NULL and lenght of zero to disable welcome message.
|
Option value type
|
binary data
|
|
Option value unit
|
N/A
|
|
Default value
|
NULL
|
|
Applicable socket types
|
ZMQ_XPUB
|
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 m[blue]http://rfc.zeromq.org/spec:27m[] 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_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.
-
Note
This option is deprecated, please use authentication via the ZAP API and IP address whitelisting / blacklisting.
|
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_IPC_FILTER_GID: Assign group ID filters to allow new IPC connections
Assign an arbitrary number of filters that will be applied for each new IPC transport connection on a listening socket. If no IPC filters are applied, then the IPC transport allows connections from any process. If at least one UID, GID, or PID filter is applied then new connection credentials should be matched. To clear all GID filters call zmq_setsockopt(socket, ZMQ_IPC_FILTER_GID, NULL, 0).
-
Note
GID filters are only available on platforms supporting SO_PEERCRED or LOCAL_PEERCRED socket options (currently only Linux and later versions of OS X).
-
Note
This option is deprecated, please use authentication via the ZAP API and IPC whitelisting / blacklisting.
|
Option value type
|
gid_t
|
|
Option value unit
|
N/A
|
|
Default value
|
no filters (allow from all)
|
|
Applicable socket types
|
all listening sockets, when using IPC transports.
|
ZMQ_IPC_FILTER_PID: Assign process ID filters to allow new IPC connections
Assign an arbitrary number of filters that will be applied for each new IPC transport connection on a listening socket. If no IPC filters are applied, then the IPC transport allows connections from any process. If at least one UID, GID, or PID filter is applied then new connection credentials should be matched. To clear all PID filters call zmq_setsockopt(socket, ZMQ_IPC_FILTER_PID, NULL, 0).
-
Note
PID filters are only available on platforms supporting the SO_PEERCRED socket option (currently only Linux).
-
Note
This option is deprecated, please use authentication via the ZAP API and IPC whitelisting / blacklisting.
|
Option value type
|
pid_t
|
|
Option value unit
|
N/A
|
|
Default value
|
no filters (allow from all)
|
|
Applicable socket types
|
all listening sockets, when using IPC transports.
|
ZMQ_IPC_FILTER_UID: Assign user ID filters to allow new IPC connections
Assign an arbitrary number of filters that will be applied for each new IPC transport connection on a listening socket. If no IPC filters are applied, then the IPC transport allows connections from any process. If at least one UID, GID, or PID filter is applied then new connection credentials should be matched. To clear all UID filters call zmq_setsockopt(socket, ZMQ_IPC_FILTER_UID, NULL, 0).
-
Note
UID filters are only available on platforms supporting SO_PEERCRED or LOCAL_PEERCRED socket options (currently only Linux and later versions of OS X).
-
Note
This option is deprecated, please use authentication via the ZAP API and IPC whitelisting / blacklisting.
|
Option value type
|
uid_t
|
|
Option value unit
|
N/A
|
|
Default value
|
no filters (allow from all)
|
|
Applicable socket types
|
all listening sockets, when using IPC 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_VMCI_BUFFER_SIZE: Set buffer size of the VMCI socket
The ZMQ_VMCI_BUFFER_SIZE option shall set the size of the underlying buffer for the socket. Used during negotiation before the connection is established.
|
Option value type
|
uint64_t
|
|
Option value unit
|
bytes
|
|
Default value
|
65546
|
|
Applicable socket types
|
all, when using VMCI transport
|
ZMQ_VMCI_BUFFER_MIN_SIZE: Set min buffer size of the VMCI socket
The ZMQ_VMCI_BUFFER_MIN_SIZE option shall set the min size of the underlying buffer for the socket. Used during negotiation before the connection is established.
|
Option value type
|
uint64_t
|
|
Option value unit
|
bytes
|
|
Default value
|
128
|
|
Applicable socket types
|
all, when using VMCI transport
|
ZMQ_VMCI_BUFFER_MAX_SIZE: Set max buffer size of the VMCI socket
The ZMQ_VMCI_BUFFER_MAX_SIZE option shall set the max size of the underlying buffer for the socket. Used during negotiation before the connection is established.
|
Option value type
|
uint64_t
|
|
Option value unit
|
bytes
|
|
Default value
|
262144
|
|
Applicable socket types
|
all, when using VMCI transport
|
ZMQ_VMCI_CONNECT_TIMEOUT: Set connection timeout of the VMCI socket
The ZMQ_VMCI_CONNECT_TIMEOUT option shall set connection timeout for the socket.
|
Option value type
|
int
|
|
Option value unit
|
milliseconds
|
|
Default value
|
-1
|
|
Applicable socket types
|
all, when using VMCI transport
|
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
This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at m[blue]http://www.zeromq.org/docs:contributingm[].
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- ZMQ_AFFINITY: Set I/O thread affinity
-
- ZMQ_BACKLOG: Set maximum length of the queue of outstanding connections
-
- ZMQ_CONNECT_RID: Assign the next outbound connection id
-
- ZMQ_CONFLATE: Keep only last message
-
- ZMQ_CONNECT_TIMEOUT: Set connect() timeout
-
- ZMQ_CURVE_PUBLICKEY: Set CURVE public key
-
- ZMQ_CURVE_SECRETKEY: Set CURVE secret key
-
- ZMQ_CURVE_SERVER: Set CURVE server role
-
- ZMQ_CURVE_SERVERKEY: Set CURVE server key
-
- ZMQ_GSSAPI_PLAINTEXT: Disable GSSAPI encryption
-
- ZMQ_GSSAPI_PRINCIPAL: Set name of GSSAPI principal
-
- ZMQ_GSSAPI_SERVER: Set GSSAPI server role
-
- ZMQ_GSSAPI_SERVICE_PRINCIPAL: Set name of GSSAPI service principal
-
- ZMQ_HANDSHAKE_IVL: Set maximum handshake interval
-
- ZMQ_HEARTBEAT_IVL: Set interval between sending ZMTP heartbeats
-
- ZMQ_HEARTBEAT_TIMEOUT: Set timeout for ZMTP heartbeats
-
- ZMQ_HEARTBEAT_TTL: Set the TTL value for ZMTP heartbeats
-
- ZMQ_IDENTITY: Set socket identity
-
- ZMQ_IMMEDIATE: Queue messages only to completed connections
-
- ZMQ_INVERT_MATCHING: Invert message filtering
-
- ZMQ_IPV6: Enable IPv6 on socket
-
- ZMQ_LINGER: Set linger period for socket shutdown
-
- ZMQ_MAXMSGSIZE: Maximum acceptable inbound message size
-
- ZMQ_MULTICAST_HOPS: Maximum network hops for multicast packets
-
- ZMQ_MULTICAST_MAXTPDU: Maximum transport data unit size for multicast packets
-
- ZMQ_PLAIN_PASSWORD: Set PLAIN security password
-
- ZMQ_PLAIN_SERVER: Set PLAIN server role
-
- ZMQ_PLAIN_USERNAME: Set PLAIN security username
-
- ZMQ_USE_FD: Set the pre-allocated socket file descriptor
-
- ZMQ_PROBE_ROUTER: bootstrap connections to ROUTER sockets
-
- ZMQ_RATE: Set multicast data rate
-
- ZMQ_RCVBUF: Set kernel receive buffer size
-
- ZMQ_RCVHWM: Set high water mark for inbound messages
-
- ZMQ_RCVTIMEO: Maximum time before a recv operation returns with EAGAIN
-
- ZMQ_RECONNECT_IVL: Set reconnection interval
-
- ZMQ_RECONNECT_IVL_MAX: Set maximum reconnection interval
-
- ZMQ_RECOVERY_IVL: Set multicast recovery interval
-
- ZMQ_REQ_CORRELATE: match replies with requests
-
- ZMQ_REQ_RELAXED: relax strict alternation between request and reply
-
- ZMQ_ROUTER_HANDOVER: handle duplicate client identities on ROUTER sockets
-
- ZMQ_ROUTER_MANDATORY: accept only routable messages on ROUTER sockets
-
- ZMQ_ROUTER_RAW: switch ROUTER socket to raw mode
-
- ZMQ_SNDBUF: Set kernel transmit buffer size
-
- ZMQ_SNDHWM: Set high water mark for outbound messages
-
- ZMQ_SNDTIMEO: Maximum time before a send operation returns with EAGAIN
-
- ZMQ_SOCKS_PROXY: Set SOCKS5 proxy address
-
- ZMQ_STREAM_NOTIFY: send connect and disconnect notifications
-
- ZMQ_SUBSCRIBE: Establish message filter
-
- ZMQ_TCP_KEEPALIVE: Override SO_KEEPALIVE socket option
-
- ZMQ_TCP_KEEPALIVE_CNT: Override TCP_KEEPCNT socket option
-
- ZMQ_TCP_KEEPALIVE_IDLE: Override TCP_KEEPIDLE (or TCP_KEEPALIVE on some OS)
-
- ZMQ_TCP_KEEPALIVE_INTVL: Override TCP_KEEPINTVL socket option
-
- ZMQ_TCP_MAXRT: Set TCP Maximum Retransmit Timeout
-
- ZMQ_TOS: Set the Type-of-Service on socket
-
- ZMQ_UNSUBSCRIBE: Remove message filter
-
- ZMQ_XPUB_VERBOSE: pass subscribe messages on XPUB socket
-
- ZMQ_XPUB_VERBOSER: pass subscribe and unsubscribe messages on XPUB socket
-
- ZMQ_XPUB_MANUAL: change the subscription handling to manual
-
- ZMQ_XPUB_NODROP: do not silently drop messages if SENDHWM is reached
-
- ZMQ_XPUB_WELCOME_MSG: set welcome message that will be received by subscriber when connecting
-
- ZMQ_ZAP_DOMAIN: Set RFC 27 authentication domain
-
- ZMQ_TCP_ACCEPT_FILTER: Assign filters to allow new TCP connections
-
- ZMQ_IPC_FILTER_GID: Assign group ID filters to allow new IPC connections
-
- ZMQ_IPC_FILTER_PID: Assign process ID filters to allow new IPC connections
-
- ZMQ_IPC_FILTER_UID: Assign user ID filters to allow new IPC connections
-
- ZMQ_IPV4ONLY: Use IPv4-only on socket
-
- ZMQ_VMCI_BUFFER_SIZE: Set buffer size of the VMCI socket
-
- ZMQ_VMCI_BUFFER_MIN_SIZE: Set min buffer size of the VMCI socket
-
- ZMQ_VMCI_BUFFER_MAX_SIZE: Set max buffer size of the VMCI socket
-
- ZMQ_VMCI_CONNECT_TIMEOUT: Set connection timeout of the VMCI socket
-
- RETURN VALUE
-
- ERRORS
-
- EXAMPLE
-
- SEE ALSO
-
- AUTHORS
-
|
|
- Running on 
-
:
: 