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Diffstat (limited to 'doc/zmq_msg_recv.3')
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diff --git a/doc/zmq_msg_recv.3 b/doc/zmq_msg_recv.3 new file mode 100644 index 0000000..3f47a8b --- /dev/null +++ b/doc/zmq_msg_recv.3 @@ -0,0 +1,177 @@ +'\" t +.\" Title: zmq_msg_recv +.\" Author: [see the "AUTHORS" section] +.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/> +.\" Date: 11/23/2012 +.\" Manual: 0MQ Manual +.\" Source: 0MQ 3.2.1 +.\" Language: English +.\" +.TH "ZMQ_MSG_RECV" "3" "11/23/2012" "0MQ 3\&.2\&.1" "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_msg_recv \- receive a message part from a socket +.SH "SYNOPSIS" +.sp +\fBint zmq_msg_recv (zmq_msg_t \fR\fB\fI*msg\fR\fR\fB, void \fR\fB\fI*socket\fR\fR\fB, int \fR\fB\fIflags\fR\fR\fB);\fR +.SH "DESCRIPTION" +.sp +The \fIzmq_msg_recv()\fR function is identical to \fBzmq_recvmsg\fR(3), which shall be deprecated in future versions\&. \fIzmq_msg_recv()\fR is more consistent with other message manipulation functions\&. +.sp +The \fIzmq_msg_recv()\fR function shall receive a message part from the socket referenced by the \fIsocket\fR argument and store it in the message referenced by the \fImsg\fR argument\&. Any content previously stored in \fImsg\fR shall be properly deallocated\&. If there are no message parts available on the specified \fIsocket\fR the \fIzmq_msg_recv()\fR function shall block until the request can be satisfied\&. The \fIflags\fR argument is a combination of the flags defined below: +.PP +\fBZMQ_DONTWAIT\fR +.RS 4 +Specifies that the operation should be performed in non\-blocking mode\&. If there are no messages available on the specified +\fIsocket\fR, the +\fIzmq_msg_recv()\fR +function shall fail with +\fIerrno\fR +set to EAGAIN\&. +.RE +.SS "Multi\-part messages" +.sp +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\&. +.sp +An application that processes multi\-part messages must use the \fIZMQ_RCVMORE\fR \fBzmq_getsockopt\fR(3) option after calling \fIzmq_msg_recv()\fR to determine if there are further parts to receive\&. +.SH "RETURN VALUE" +.sp +The \fIzmq_msg_recv()\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\&. +.SH "ERRORS" +.PP +\fBEAGAIN\fR +.RS 4 +Non\-blocking mode was requested and no messages are available at the moment\&. +.RE +.PP +\fBENOTSUP\fR +.RS 4 +The +\fIzmq_msg_recv()\fR +operation is not supported by this socket type\&. +.RE +.PP +\fBEFSM\fR +.RS 4 +The +\fIzmq_msg_recv()\fR +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 +\fImessaging patterns\fR +section of +\fBzmq_socket\fR(3) +for more information\&. +.RE +.PP +\fBETERM\fR +.RS 4 +The 0MQ +\fIcontext\fR +associated with the specified +\fIsocket\fR +was terminated\&. +.RE +.PP +\fBENOTSOCK\fR +.RS 4 +The provided +\fIsocket\fR +was invalid\&. +.RE +.PP +\fBEINTR\fR +.RS 4 +The operation was interrupted by delivery of a signal before a message was available\&. +.RE +.PP +\fBEFAULT\fR +.RS 4 +The message passed to the function was invalid\&. +.RE +.SH "EXAMPLE" +.PP +\fBReceiving a message from a socket\fR. +.sp +.if n \{\ +.RS 4 +.\} +.nf +/* Create an empty 0MQ message */ +zmq_msg_t msg; +int rc = zmq_msg_init (&msg); +assert (rc == 0); +/* Block until a message is available to be received from socket */ +rc = zmq_msg_recv (&msg, socket, 0); +assert (rc != \-1); +/* Release message */ +zmq_msg_close (&msg); +.fi +.if n \{\ +.RE +.\} +.PP +\fBReceiving a multi-part message\fR. +.sp +.if n \{\ +.RS 4 +.\} +.nf +int64_t more; +size_t more_size = sizeof more; +do { + /* Create an empty 0MQ message to hold the message part */ + zmq_msg_t part; + int rc = zmq_msg_init (&part); + assert (rc == 0); + /* Block until a message is available to be received from socket */ + rc = zmq_msg_recv (&part, socket, 0); + assert (rc != \-1); + /* Determine if more message parts are to follow */ + rc = zmq_getsockopt (socket, ZMQ_RCVMORE, &more, &more_size); + assert (rc == 0); + zmq_msg_close (&part); +} while (more); +.fi +.if n \{\ +.RE +.\} +.sp +.SH "SEE ALSO" +.sp +\fBzmq_recv\fR(3) \fBzmq_send\fR(3) \fBzmq_msg_send\fR(3) \fBzmq_getsockopt\fR(3) \fBzmq_socket\fR(7) \fBzmq\fR(7) +.SH "AUTHORS" +.sp +This man page was written by Martin Sustrik <\m[blue]\fBsustrik@250bpm\&.com\fR\m[]\&\s-2\u[1]\d\s+2>, Martin Lucina <\m[blue]\fBmartin@lucina\&.net\fR\m[]\&\s-2\u[2]\d\s+2>, and Pieter Hintjens <\m[blue]\fBph@imatix\&.com\fR\m[]\&\s-2\u[3]\d\s+2>\&. +.SH "NOTES" +.IP " 1." 4 +sustrik@250bpm.com +.RS 4 +\%mailto:sustrik@250bpm.com +.RE +.IP " 2." 4 +martin@lucina.net +.RS 4 +\%mailto:martin@lucina.net +.RE +.IP " 3." 4 +ph@imatix.com +.RS 4 +\%mailto:ph@imatix.com +.RE |