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199 lines
5.7 KiB
199 lines
5.7 KiB
6 years ago
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'\" t
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.\" Title: zmq_sendmsg
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.\" Author: [see the "AUTHORS" section]
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.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
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.\" Date: 02/18/2017
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.\" Manual: 0MQ Manual
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.\" Source: 0MQ 4.2.2
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.\" Language: English
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.\"
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.TH "ZMQ_SENDMSG" "3" "02/18/2017" "0MQ 4\&.2\&.2" "0MQ Manual"
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.\" -----------------------------------------------------------------
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.\" * Define some portability stuff
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.\" -----------------------------------------------------------------
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.\" http://bugs.debian.org/507673
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.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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.ie \n(.g .ds Aq \(aq
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.el .ds Aq '
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.\" -----------------------------------------------------------------
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.\" * set default formatting
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.\" -----------------------------------------------------------------
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.\" disable hyphenation
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.nh
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.\" disable justification (adjust text to left margin only)
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.ad l
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.\" -----------------------------------------------------------------
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.\" * MAIN CONTENT STARTS HERE *
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.\" -----------------------------------------------------------------
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.SH "NAME"
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zmq_sendmsg \- send a message part on a socket
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.SH "SYNOPSIS"
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.sp
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\fBint zmq_sendmsg (void \fR\fB\fI*socket\fR\fR\fB, zmq_msg_t \fR\fB\fI*msg\fR\fR\fB, int \fR\fB\fIflags\fR\fR\fB);\fR
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.SH "DESCRIPTION"
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.sp
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The \fIzmq_sendmsg()\fR function shall queue the message referenced by the \fImsg\fR argument to be sent to the socket referenced by the \fIsocket\fR argument\&. The \fIflags\fR argument is a combination of the flags defined below:
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.PP
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\fBZMQ_DONTWAIT\fR
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.RS 4
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For socket types (DEALER, PUSH) that block when there are no available peers (or all peers have full high\-water mark), specifies that the operation should be performed in non\-blocking mode\&. If the message cannot be queued on the
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\fIsocket\fR, the
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\fIzmq_sendmsg()\fR
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function shall fail with
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\fIerrno\fR
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set to EAGAIN\&.
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.RE
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.PP
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\fBZMQ_SNDMORE\fR
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.RS 4
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Specifies that the message being sent is a multi\-part message, and that further message parts are to follow\&. Refer to the section regarding multi\-part messages below for a detailed description\&.
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.RE
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.sp
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The \fIzmq_msg_t\fR structure passed to \fIzmq_sendmsg()\fR is nullified during the call\&. If you want to send the same message to multiple sockets you have to copy it (e\&.g\&. using \fIzmq_msg_copy()\fR)\&.
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.if n \{\
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.sp
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.\}
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.RS 4
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.it 1 an-trap
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.nr an-no-space-flag 1
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.nr an-break-flag 1
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.br
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.ps +1
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\fBNote\fR
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.ps -1
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.br
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.sp
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A successful invocation of \fIzmq_sendmsg()\fR does not indicate that the message has been transmitted to the network, only that it has been queued on the \fIsocket\fR and 0MQ has assumed responsibility for the message\&.
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.sp .5v
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.RE
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.if n \{\
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.sp
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.\}
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.RS 4
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.it 1 an-trap
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.nr an-no-space-flag 1
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.nr an-break-flag 1
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.br
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.ps +1
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\fBNote\fR
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.ps -1
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.br
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.sp
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this API method is deprecated in favor of zmq_msg_send(3)\&.
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.sp .5v
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.RE
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.SS "Multi\-part messages"
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.sp
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A 0MQ message is composed of 1 or more message parts\&. Each message part is an independent \fIzmq_msg_t\fR in its own right\&. 0MQ ensures atomic delivery of messages: peers shall receive either all \fImessage parts\fR of a message or none at all\&. The total number of message parts is unlimited except by available memory\&.
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.sp
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An application that sends multi\-part messages must use the \fIZMQ_SNDMORE\fR flag when sending each message part except the final one\&.
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.SH "RETURN VALUE"
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.sp
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The \fIzmq_sendmsg()\fR function shall return number of bytes in the message if successful\&. Otherwise it shall return \-1 and set \fIerrno\fR to one of the values defined below\&.
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.SH "ERRORS"
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.PP
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\fBEAGAIN\fR
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.RS 4
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Non\-blocking mode was requested and the message cannot be sent at the moment\&.
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.RE
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.PP
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\fBENOTSUP\fR
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.RS 4
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The
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\fIzmq_sendmsg()\fR
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operation is not supported by this socket type\&.
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.RE
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.PP
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\fBEINVAL\fR
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.RS 4
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The sender tried to send multipart data, which the socket type does not allow\&.
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.RE
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.PP
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\fBEFSM\fR
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.RS 4
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The
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\fIzmq_sendmsg()\fR
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operation cannot be performed on this socket at the moment due to the socket not being in the appropriate state\&. This error may occur with socket types that switch between several states, such as ZMQ_REP\&. See the
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\fImessaging patterns\fR
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section of
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\fBzmq_socket\fR(3)
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for more information\&.
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.RE
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.PP
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\fBETERM\fR
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.RS 4
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The 0MQ
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\fIcontext\fR
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associated with the specified
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\fIsocket\fR
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was terminated\&.
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.RE
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.PP
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\fBENOTSOCK\fR
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.RS 4
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The provided
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\fIsocket\fR
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was invalid\&.
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.RE
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.PP
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\fBEINTR\fR
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.RS 4
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The operation was interrupted by delivery of a signal before the message was sent\&.
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.RE
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.PP
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\fBEFAULT\fR
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.RS 4
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Invalid message\&.
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.RE
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.PP
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\fBEHOSTUNREACH\fR
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.RS 4
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The message cannot be routed\&.
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.RE
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.SH "EXAMPLE"
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.PP
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\fBFilling in a message and sending it to a socket\fR.
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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/* Create a new message, allocating 6 bytes for message content */
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zmq_msg_t msg;
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int rc = zmq_msg_init_size (&msg, 6);
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assert (rc == 0);
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/* Fill in message content with \*(AqAAAAAA\*(Aq */
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memset (zmq_msg_data (&msg), \*(AqA\*(Aq, 6);
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/* Send the message to the socket */
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rc = zmq_sendmsg (socket, &msg, 0);
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assert (rc == 6);
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.fi
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.if n \{\
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.RE
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.\}
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.PP
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\fBSending a multi-part message\fR.
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.sp
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.if n \{\
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.RS 4
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.\}
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.nf
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/* Send a multi\-part message consisting of three parts to socket */
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rc = zmq_sendmsg (socket, &part1, ZMQ_SNDMORE);
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rc = zmq_sendmsg (socket, &part2, ZMQ_SNDMORE);
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/* Final part; no more parts to follow */
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rc = zmq_sendmsg (socket, &part3, 0);
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.fi
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.if n \{\
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.RE
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.\}
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.sp
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.SH "SEE ALSO"
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.sp
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\fBzmq_recv\fR(3) \fBzmq_socket\fR(7) \fBzmq\fR(7)
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.SH "AUTHORS"
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.sp
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This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.
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