zeromq-3.2.5.tar.gz

zmq_getsockopt(3) ================= NAME ---- zmq_getsockopt - get 0MQ socket options SYNOPSIS -------- *int zmq_getsockopt (void '*socket', int 'option_name', void '*option_value', size_t '*option_len');* DESCRIPTION ----------- The _zmq_getsockopt()_ function shall retrieve the value for the option specified by the 'option_name' argument for the 0MQ socket pointed to by the 'socket' argument, and store it in the buffer pointed to by the 'option_value' argument. The 'option_len' argument is the size in bytes of the buffer pointed to by 'option_value'; upon successful completion _zmq_getsockopt()_ shall modify the 'option_len' argument to indicate the actual size of the option value stored in the buffer. The following options can be retrieved with the _zmq_getsockopt()_ function: ZMQ_TYPE: Retrieve socket type ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_TYPE' option shall retrieve the socket type for the specified 'socket'. The socket type is specified at socket creation time and cannot be modified afterwards. [horizontal] Option value type:: int Option value unit:: N/A Default value:: N/A Applicable socket types:: all ZMQ_RCVMORE: More message data parts to follow ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_RCVMORE' option shall return True (1) if the message part last received from the 'socket' was a data part with more parts to follow. If there are no data parts to follow, this option shall return False (0). Refer to linkzmq:zmq_send[3] and linkzmq:zmq_recv[3] for a detailed description of multi-part messages. [horizontal] Option value type:: int Option value unit:: boolean Default value:: N/A Applicable socket types:: all ZMQ_SNDHWM: Retrieves high water mark for outbound messages ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_SNDHWM' option shall return 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. 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 linkzmq:zmq_socket[3] for details on the exact action taken for each socket type. [horizontal] Option value type:: int Option value unit:: messages Default value:: 1000 Applicable socket types:: all ZMQ_RCVHWM: Retrieve high water mark for inbound messages ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_RCVHWM' option shall return 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. 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 linkzmq:zmq_socket[3] for details on the exact action taken for each socket type. [horizontal] Option value type:: int Option value unit:: messages Default value:: 1000 Applicable socket types:: all ZMQ_AFFINITY: Retrieve I/O thread affinity ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_AFFINITY' option shall retrieve 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 linkzmq:zmq_init[3] for details on allocating the number of I/O threads for a specific _context_. [horizontal] Option value type:: uint64_t Option value unit:: N/A (bitmap) Default value:: 0 Applicable socket types:: N/A ZMQ_IDENTITY: Set socket identity ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_IDENTITY' option shall retrieve the identity of the specified 'socket'. Socket identity is used only by request/reply pattern. Namely, it can be used in tandem with ROUTER socket to route messages to the peer with specific identity. Identity should be at least one byte and at most 255 bytes long. Identities starting with binary zero are reserved for use by 0MQ infrastructure. [horizontal] Option value type:: binary data Option value unit:: N/A Default value:: NULL Applicable socket types:: all ZMQ_RATE: Retrieve multicast data rate ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_RATE' option shall retrieve the maximum send or receive data rate for multicast transports using the specified 'socket'. [horizontal] Option value type:: int Option value unit:: kilobits per second Default value:: 100 Applicable socket types:: all, when using multicast transports ZMQ_RECOVERY_IVL: Get multicast recovery interval ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_RECOVERY_IVL' option shall retrieve 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. [horizontal] Option value type:: int Option value unit:: milliseconds Default value:: 10000 Applicable socket types:: all, when using multicast transports ZMQ_SNDBUF: Retrieve kernel transmit buffer size ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_SNDBUF' option shall retrieve the underlying kernel transmit buffer size for the specified 'socket'. A value of zero means that the OS default is in effect. For details refer to your operating system documentation for the 'SO_SNDBUF' socket option. [horizontal] Option value type:: int Option value unit:: bytes Default value:: 0 Applicable socket types:: all ZMQ_RCVBUF: Retrieve kernel receive buffer size ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_RCVBUF' option shall retrieve the underlying kernel receive buffer size for the specified 'socket'. A value of zero means that the OS default is in effect. For details refer to your operating system documentation for the 'SO_RCVBUF' socket option. [horizontal] Option value type:: int Option value unit:: bytes Default value:: 0 Applicable socket types:: all ZMQ_LINGER: Retrieve linger period for socket shutdown ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The 'ZMQ_LINGER' option shall retrieve 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 linkzmq:zmq_close[3], and further affects the termination of the socket's context with linkzmq: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 m