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Add zmq_getsockopt(3), clean up zmq_setsockopt(3).
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Martin Lucina 2010-05-31 12:53:40 +02:00
parent be6019abd1
commit 8becacf82c
2 changed files with 241 additions and 30 deletions
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209
doc/zmq_getsockopt.txt Normal file
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@ -0,0 +1,209 @@
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>.

62
doc/zmq_setsockopt.txt
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@ -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' for the 0MQ socket pointed to by the 'socket' argument. The 'option_len'
argument is the size of the option value in bytes. 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 ZMQ_HWM: Set high water mark
~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_HWM' option shall set the high water mark for the _message queue_ 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 associated with the specified 'socket'. The high water mark is a hard limit on
of outstanding messages in the queue; if this limit has been reached the socket the number of outstanding messages in the queue; if this limit has been reached
shall enter an "emergency" state and depending on the socket type, 0MQ shall the socket shall enter an "emergency" state and depending on the socket type,
take appropriate action such as blocking or dropping new messages entering the 0MQ shall take appropriate action such as blocking or dropping new messages
queue. entering the queue.
The default 'ZMQ_HWM' value of zero means "no limit". The default 'ZMQ_HWM' value of zero means "no limit".
@ -43,9 +43,10 @@ Applicable socket types:: all
ZMQ_SWAP: Set disk offload size ZMQ_SWAP: Set disk offload size
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_SWAP' option shall set the disk offload (swap) size for the _message 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 queue_ associated with the specified 'socket'. A socket which has 'ZMQ_SWAP'
non-zero value may exceed it's high water mark; in this case outstanding set to a non-zero value may exceed it's high water mark; in this case
messages shall be offloaded to storage on disk rather than held in memory. 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. 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 ZMQ_AFFINITY: Set I/O thread affinity
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_AFFINITY' option shall set the I/O thread affinity for connections The 'ZMQ_AFFINITY' option shall set the I/O thread affinity for newly created
created by subsequent _zmq_connect()_ or _zmq_bind()_ calls on the specified connections on the specified 'socket'.
'socket'.
Affinity determines which threads from the 0MQ I/O thread pool associated with 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 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 ZMQ_IDENTITY: Set socket identity
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_IDENTITY' option shall set the identity of the socket. Socket identity The 'ZMQ_IDENTITY' option shall set the identity of the specified 'socket'.
determines if existing 0MQ infastructure (_message queues_, _forwarding Socket identity determines if existing 0MQ infastructure (_message queues_,
devices_) shall be identified with a specific application and persist across _forwarding devices_) shall be identified with a specific application and
multiple runs of the application. persist across multiple runs of the application.
If the socket has no identity, each run of an application is completely 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 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 ZMQ_RECOVERY_IVL: Set multicast recovery interval
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_RECOVERY_IVL' option shall set the recovery interval for multicast The 'ZMQ_RECOVERY_IVL' option shall set the recovery interval for multicast
transports such as linkzmq:zmq_pgm[7] using the specified 'socket'. The transports using the specified 'socket'. The recovery interval determines the
recovery interval determines the maximum time in seconds that a receiver can be maximum time in seconds that a receiver can be absent from a multicast group
absent from a multicast group before unrecoverable data loss will occur. before unrecoverable data loss will occur.
CAUTION: Excersize care when setting large recovery intervals as the data 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 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 ZMQ_MCAST_LOOP: Control multicast loopback
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_MCAST_LOOP' option shall control whether data sent via multicast 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 transports using the specified 'socket' can also be received by the sending
zero disables the loopback functionality, while the default value of 1 enables host via loopback. A value of zero disables the loopback functionality, while
the loopback functionality. Leaving multicast loopback enabled when it is not the default value of 1 enables the loopback functionality. Leaving multicast
required can have a negative impact on performance. Where possible, disable loopback enabled when it is not required can have a negative impact on
'ZMQ_MCAST_LOOP' in production environments. performance. Where possible, disable 'ZMQ_MCAST_LOOP' in production
environments.
Option value type:: uint64_t Option value type:: uint64_t
Option value unit:: boolean Option value unit:: boolean
@ -178,8 +179,8 @@ Applicable socket types:: all, when using multicast transports
ZMQ_SNDBUF: Set kernel transmit buffer size ZMQ_SNDBUF: Set kernel transmit buffer size
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_SNDBUF' option shall set the underlying 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 for the 'socket' to the specified size in bytes. A value of zero means leave
OS default unchanged. For details please refer to your operating system the OS default unchanged. For details please refer to your operating system
documentation for the 'SO_SNDBUF' socket option. documentation for the 'SO_SNDBUF' socket option.
Option value type:: uint64_t Option value type:: uint64_t
@ -191,9 +192,9 @@ Applicable socket types:: all
ZMQ_RCVBUF: Set kernel receive buffer size ZMQ_RCVBUF: Set kernel receive buffer size
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The 'ZMQ_RCVBUF' option shall set the underlying kernel receive buffer size for 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 the 'socket' to the specified size in bytes. A value of zero means leave the
default unchanged. For details refer to your operating system documentation for OS default unchanged. For details refer to your operating system documentation
the 'SO_RCVBUF' socket option. for the 'SO_RCVBUF' socket option.
Option value type:: uint64_t Option value type:: uint64_t
Option value unit:: bytes 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. _option_value_ is invalid.
*ETERM*:: *ETERM*::
The associated context was terminted. The 0MQ 'context' associated with the specified 'socket' was terminated.
EXAMPLE EXAMPLE
@ -248,6 +249,7 @@ assert (rc);
SEE ALSO SEE ALSO
-------- --------
linkzmq:zmq_getsockopt[3]
linkzmq:zmq_socket[3] linkzmq:zmq_socket[3]
linkzmq:zmq[7] linkzmq:zmq[7]