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diff --git a/doc/zmq_getsockopt.3 b/doc/zmq_getsockopt.3 new file mode 100644 index 0000000..90edfd4 --- /dev/null +++ b/doc/zmq_getsockopt.3 @@ -0,0 +1,505 @@ +'\" t +.\" Title: zmq_getsockopt +.\" Author: [see the "AUTHORS" section] +.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/> +.\" Date: 06/04/2010 +.\" Manual: 0MQ Manual +.\" Source: 0MQ 2.0.7 +.\" Language: English +.\" +.TH "ZMQ_GETSOCKOPT" "3" "06/04/2010" "0MQ 2\&.0\&.7" "0MQ Manual" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +zmq_getsockopt \- get 0MQ socket options +.SH "SYNOPSIS" +.sp +\fBint zmq_getsockopt (void \fR\fB\fI*socket\fR\fR\fB, int \fR\fB\fIoption_name\fR\fR\fB, void \fR\fB\fI*option_value\fR\fR\fB, size_t \fR\fB\fI*option_len\fR\fR\fB);\fR +.SH "DESCRIPTION" +.sp +The \fIzmq_getsockopt()\fR function shall retrieve the value for the option specified by the \fIoption_name\fR argument for the 0MQ socket pointed to by the \fIsocket\fR argument, and store it in the buffer pointed to by the \fIoption_value\fR argument\&. The \fIoption_len\fR argument is the size in bytes of the buffer pointed to by \fIoption_value\fR; upon successful completion \fIzmq_getsockopt()\fR shall modify the \fIoption_value\fR argument to indicate the actual size of the option value stored in the buffer\&. +.sp +The following options can be retrieved with the \fIzmq_getsockopt()\fR function: +.SS "ZMQ_RCVMORE: More message parts to follow" +.sp +The \fIZMQ_RCVMORE\fR option shall return a boolean value indicating if the multi\-part message currently being read from the specified \fIsocket\fR has more message parts to follow\&. If there are no message parts to follow or if the message currently being read is not a multi\-part message a value of zero shall be returned\&. Otherwise, a value of 1 shall be returned\&. +.sp +Refer to \fBzmq_send\fR(3) and \fBzmq_recv\fR(3) for a detailed description of sending/receiving multi\-part messages\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +int64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +boolean +T} +T{ +.sp +Default value +T}:T{ +.sp +N/A +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SS "ZMQ_HWM: Retrieve high water mark" +.sp +The \fIZMQ_HWM\fR option shall retrieve the high water mark for the specified \fIsocket\fR\&. 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 \fIsocket\fR is communicating with\&. +.sp +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 \fBzmq_socket\fR(3) for details on the exact action taken for each socket type\&. +.sp +The default \fIZMQ_HWM\fR value of zero means "no limit"\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +int64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +messages +T} +T{ +.sp +Default value +T}:T{ +.sp +0 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SS "ZMQ_SWAP: Retrieve disk offload size" +.sp +The \fIZMQ_SWAP\fR option shall retrieve the disk offload (swap) size for the specified \fIsocket\fR\&. A socket which has \fIZMQ_SWAP\fR set to a non\-zero value may exceed it\(cqs high water mark; in this case outstanding messages shall be offloaded to storage on disk rather than held in memory\&. +.sp +The value of \fIZMQ_SWAP\fR defines the maximum size of the swap space in bytes\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +int64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +bytes +T} +T{ +.sp +Default value +T}:T{ +.sp +0 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SS "ZMQ_AFFINITY: Retrieve I/O thread affinity" +.sp +The \fIZMQ_AFFINITY\fR option shall retrieve the I/O thread affinity for newly created connections on the specified \fIsocket\fR\&. +.sp +Affinity determines which threads from the 0MQ I/O thread pool associated with the socket\(cqs \fIcontext\fR 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 \fIsocket\fR shall be handled exclusively by I/O threads 1 and 2\&. +.sp +See also \fBzmq_init\fR(3) for details on allocating the number of I/O threads for a specific \fIcontext\fR\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +int64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +N/A (bitmap) +T} +T{ +.sp +Default value +T}:T{ +.sp +0 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +N/A +T} +.TE +.sp 1 +.SS "ZMQ_IDENTITY: Retrieve socket identity" +.sp +The \fIZMQ_IDENTITY\fR option shall retrieve the identity of the specified \fIsocket\fR\&. Socket identity determines if existing 0MQ infastructure (\fImessage queues\fR, \fIforwarding devices\fR) shall be identified with a specific application and persist across multiple runs of the application\&. +.sp +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, \fImessage queue\fR limits shall be shared with previous run(s) and so on\&. +.sp +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\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +binary data +T} +T{ +.sp +Option value unit +T}:T{ +.sp +N/A +T} +T{ +.sp +Default value +T}:T{ +.sp +NULL +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SS "ZMQ_RATE: Retrieve multicast data rate" +.sp +The \fIZMQ_RATE\fR option shall retrieve the maximum send or receive data rate for multicast transports using the specified \fIsocket\fR\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +uint64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +kilobits per second +T} +T{ +.sp +Default value +T}:T{ +.sp +100 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all, when using multicast transports +T} +.TE +.sp 1 +.SS "ZMQ_RECOVERY_IVL: Get multicast recovery interval" +.sp +The \fIZMQ_RECOVERY_IVL\fR option shall retrieve the recovery interval for multicast transports using the specified \fIsocket\fR\&. 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\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +uint64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +seconds +T} +T{ +.sp +Default value +T}:T{ +.sp +10 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all, when using multicast transports +T} +.TE +.sp 1 +.SS "ZMQ_MCAST_LOOP: Control multicast loopback" +.sp +The \fIZMQ_MCAST_LOOP\fR 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 \fIZMQ_MCAST_LOOP\fR in production environments\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +uint64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +boolean +T} +T{ +.sp +Default value +T}:T{ +.sp +1 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all, when using multicast transports +T} +.TE +.sp 1 +.SS "ZMQ_SNDBUF: Retrieve kernel transmit buffer size" +.sp +The \fIZMQ_SNDBUF\fR option shall retrieve the underlying kernel transmit buffer size for the specified \fIsocket\fR\&. A value of zero means that the OS default is in effect\&. For details refer to your operating system documentation for the \fISO_SNDBUF\fR socket option\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +uint64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +bytes +T} +T{ +.sp +Default value +T}:T{ +.sp +0 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SS "ZMQ_RCVBUF: Retrieve kernel receive buffer size" +.sp +The \fIZMQ_RCVBUF\fR option shall retrieve the underlying kernel receive buffer size for the specified \fIsocket\fR\&. A value of zero means that the OS default is in effect\&. For details refer to your operating system documentation for the \fISO_RCVBUF\fR socket option\&. +.TS +tab(:); +lt lt +lt lt +lt lt +lt lt. +T{ +.sp +Option value type +T}:T{ +.sp +uint64_t +T} +T{ +.sp +Option value unit +T}:T{ +.sp +bytes +T} +T{ +.sp +Default value +T}:T{ +.sp +0 +T} +T{ +.sp +Applicable socket types +T}:T{ +.sp +all +T} +.TE +.sp 1 +.SH "RETURN VALUE" +.sp +The \fIzmq_getsockopt()\fR function shall return zero if successful\&. Otherwise it shall return \-1 and set \fIerrno\fR to one of the values defined below\&. +.SH "ERRORS" +.PP +\fBEINVAL\fR +.RS 4 +The requested option +\fIoption_name\fR +is unknown, or the requested +\fIoption_len\fR +or +\fIoption_value\fR +is invalid, or the size of the buffer pointed to by +\fIoption_value\fR, as specified by +\fIoption_len\fR, is insufficient for storing the option value\&. +.RE +.PP +\fBETERM\fR +.RS 4 +The 0MQ +\fIcontext\fR +associated with the specified +\fIsocket\fR +was terminated\&. +.RE +.SH "EXAMPLE" +.PP +\fBRetrieving the high water mark\fR. +.sp +.if n \{\ +.RS 4 +.\} +.nf +/* Retrieve high water mark into hwm */ +int64_t hwm; +rc = zmq_getsockopt (socket, ZMQ_HWM, &hwm, sizeof hwm); +assert (rc == 0); +.fi +.if n \{\ +.RE +.\} +.sp +.SH "SEE ALSO" +.sp +\fBzmq_setsockopt\fR(3) \fBzmq_socket\fR(3) \fBzmq\fR(7) +.SH "AUTHORS" +.sp +The 0MQ documentation was written by Martin Sustrik <\m[blue]\fBsustrik@250bpm\&.com\fR\m[]\&\s-2\u[1]\d\s+2> and Martin Lucina <\m[blue]\fBmato@kotelna\&.sk\fR\m[]\&\s-2\u[2]\d\s+2>\&. +.SH "NOTES" +.IP " 1." 4 +sustrik@250bpm.com +.RS 4 +\%mailto:sustrik@250bpm.com +.RE +.IP " 2." 4 +mato@kotelna.sk +.RS 4 +\%mailto:mato@kotelna.sk +.RE |