Documentation updates

Add zmq_getsockopt(3), clean up zmq_setsockopt(3).

doc/zmq_getsockopt.txt

+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'.
+
+The following options can be retrieved with the _zmq_getsockopt()_ function:
+
+
+ZMQ_HWM: Retrieve high water mark
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_HWM' option shall retrieve the high water mark for the _message queue_
+associated with the specified 'socket'.  The high water mark is a hard limit on
+the number of outstanding messages in the queue; if this limit has been reached
+the socket shall enter an "emergency" state and depending on the socket type,
+0MQ shall take appropriate action such as blocking or dropping new messages
+entering the queue.
+
+The default 'ZMQ_HWM' value of zero means "no limit".
+
+Option value type:: int64_t
+Option value unit:: messages
+Default value:: 0
+Applicable socket types:: all
+
+
+ZMQ_SWAP: Retrieve disk offload size
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_SWAP' option shall retrieve the disk offload (swap) size for the
+_message queue_ associated with the specified 'socket'. A socket which has
+'ZMQ_SWAP' set to a non-zero value may exceed it's high water mark; in this
+case outstanding messages shall be offloaded to storage on disk rather than
+held in memory.
+
+The value of 'ZMQ_SWAP' defines the maximum size of the swap space in bytes.
+
+Option value type:: int64_t
+Option value unit:: bytes
+Default value:: 0
+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_.
+
+Option value type:: int64_t
+Option value unit:: N/A (bitmap)
+Default value:: 0
+Applicable socket types:: N/A
+
+
+ZMQ_IDENTITY: Retrieve socket identity
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_IDENTITY' option shall retrieve the identity of the specified
+'socket'. Socket identity determines if existing 0MQ infastructure (_message
+queues_, _forwarding devices_) shall be identified with a specific application
+and persist across multiple runs of the application.
+
+If the socket has no identity, each run of an application is completely
+separate from other runs. However, with identity set the socket shall re-use
+any existing 0MQ infrastructure configured by the previous run(s). Thus the
+application may receive messages that were sent in the meantime, _message
+queue_ limits shall be shared with previous run(s) and so on.
+
+Identity can be at least one byte and at most 255 bytes long. Identities
+starting with binary zero are reserved for use by 0MQ infrastructure.
+
+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'.
+
+Option value type:: uint64_t
+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 seconds that a receiver can be absent from a
+multicast group before unrecoverable data loss will occur.
+
+Option value type:: uint64_t
+Option value unit:: seconds
+Default value:: 10
+Applicable socket types:: all, when using multicast transports
+
+
+ZMQ_MCAST_LOOP: Control multicast loopback
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_MCAST_LOOP' option controls whether data sent via multicast
+transports can also be received by the sending host via loopback.  A value of
+zero indicates that the loopback functionality is disabled, while the default
+value of 1 indicates that the loopback functionality is enabled.  Leaving
+multicast loopback enabled when it is not required can have a negative impact
+on performance. Where possible, disable 'ZMQ_MCAST_LOOP' in production
+environments.
+
+Option value type:: uint64_t
+Option value unit:: boolean
+Default value:: 1
+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.
+
+Option value type:: uint64_t
+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.
+
+Option value type:: uint64_t
+Option value unit:: bytes
+Default value:: 0
+Applicable socket types:: all
+
+
+RETURN VALUE
+------------
+The _zmq_getsockopt()_ 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, or the size of the buffer pointed to by
+_option_value_, as specified by _option_len_, is insufficient for storing the
+option value.
+
+*ETERM*::
+The 0MQ 'context' associated with the specified 'socket' was terminated.
+
+
+EXAMPLE
+-------
+.Retrieving the high water mark
+----
+/* Retrieve high water mark into hwm */
+int64_t hwm;
+rc = zmq_getsockopt (socket, ZMQ_HWM, &hwm, sizeof hwm);
+assert (rc == 0);
+----
+
+
+SEE ALSO
+--------
+linkzmq:zmq_setsockopt[3]
+linkzmq:zmq_socket[3]
+linkzmq:zmq[7]
+
+
+AUTHORS
+-------
+The 0MQ documentation was written by Martin Sustrik <sustrik@250bpm.com> and
+Martin Lucina <mato@kotelna.sk>.

doc/zmq_setsockopt.txt

@@ -20,17 +20,17 @@ The _zmq_setsockopt()_ function shall set the option specified by the
 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 options are defined:
+The following socket options can be set with the _zmq_setsockopt()_ function:
 
 
 ZMQ_HWM: Set high water mark
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_HWM' option shall set the high water mark for the _message queue_
-associated with the socket.  The high water mark is a hard limit on the number
-of outstanding messages in the queue; if this limit has been reached the socket
-shall enter an "emergency" state and depending on the socket type, 0MQ shall
-take appropriate action such as blocking or dropping new messages entering the
-queue.
+associated with the specified 'socket'.  The high water mark is a hard limit on
+the number of outstanding messages in the queue; if this limit has been reached
+the socket shall enter an "emergency" state and depending on the socket type,
+0MQ shall take appropriate action such as blocking or dropping new messages
+entering the queue.
 
 The default 'ZMQ_HWM' value of zero means "no limit".
 
@@ -43,9 +43,10 @@ Applicable socket types:: all
 ZMQ_SWAP: Set disk offload size
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_SWAP' option shall set the disk offload (swap) size for the _message
-queue_ associated with the socket. A socket which has 'ZMQ_SWAP' set to a
-non-zero value may exceed it's high water mark; in this case outstanding
-messages shall be offloaded to storage on disk rather than held in memory.
+queue_ associated with the specified 'socket'. A socket which has 'ZMQ_SWAP'
+set to a non-zero value may exceed it's high water mark; in this case
+outstanding messages shall be offloaded to storage on disk rather than held in
+memory.
 
 The value of 'ZMQ_SWAP' defines the maximum size of the swap space in bytes.
 
@@ -57,9 +58,8 @@ Applicable socket types:: all
 
 ZMQ_AFFINITY: Set I/O thread affinity
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The 'ZMQ_AFFINITY' option shall set the I/O thread affinity for connections
-created by subsequent _zmq_connect()_ or _zmq_bind()_ calls on the specified
-'socket'.
+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
@@ -80,10 +80,10 @@ Applicable socket types:: N/A
 
 ZMQ_IDENTITY: Set socket identity
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The 'ZMQ_IDENTITY' option shall set the identity of the socket. Socket identity
-determines if existing 0MQ infastructure (_message queues_, _forwarding
-devices_) shall be identified with a specific application and persist across
-multiple runs of the application.
+The 'ZMQ_IDENTITY' option shall set the identity of the specified 'socket'.
+Socket identity determines if existing 0MQ infastructure (_message queues_,
+_forwarding devices_) shall be identified with a specific application and
+persist across multiple runs of the application.
 
 If the socket has no identity, each run of an application is completely
 separate from other runs. However, with identity set the socket shall re-use
@@ -146,9 +146,9 @@ 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 such as linkzmq:zmq_pgm[7] using the specified 'socket'. The
-recovery interval determines the maximum time in seconds that a receiver can be
-absent from a multicast group before unrecoverable data loss will occur.
+transports using the specified 'socket'. The recovery interval determines the
+maximum time in seconds that a receiver can be absent from a multicast group
+before unrecoverable data loss will occur.
 
 CAUTION: Excersize care when setting large recovery intervals as the data
 needed for recovery will be held in memory. For example, a 1 minute recovery
@@ -163,11 +163,12 @@ Applicable socket types:: all, when using multicast transports
 ZMQ_MCAST_LOOP: Control multicast loopback
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 The 'ZMQ_MCAST_LOOP' option shall control whether data sent via multicast
-transports can also be received by the sending host via loopback.  A value of
-zero disables the loopback functionality, while the default value of 1 enables
-the loopback functionality. Leaving multicast loopback enabled when it is not
-required can have a negative impact on performance. Where possible, disable
-'ZMQ_MCAST_LOOP' in production environments.
+transports using the specified 'socket' can also be received by the sending
+host via loopback. A value of zero disables the loopback functionality, while
+the default value of 1 enables the loopback functionality. Leaving multicast
+loopback enabled when it is not required can have a negative impact on
+performance. Where possible, disable 'ZMQ_MCAST_LOOP' in production
+environments.
 
 Option value type:: uint64_t
 Option value unit:: boolean
@@ -178,8 +179,8 @@ 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
+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:: uint64_t
@@ -191,9 +192,9 @@ 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.
+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:: uint64_t
 Option value unit:: bytes
@@ -214,7 +215,7 @@ The requested option _option_name_ is unknown, or the requested _option_len_ or
 _option_value_ is invalid.
 
 *ETERM*::
-The associated context was terminted.
+The 0MQ 'context' associated with the specified 'socket' was terminated.
 
 
 EXAMPLE
@@ -248,6 +249,7 @@ assert (rc);
 
 SEE ALSO
 --------
+linkzmq:zmq_getsockopt[3]
 linkzmq:zmq_socket[3]
 linkzmq:zmq[7]