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'\" t
.\"     Title: zmq_msg_get
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 01/17/2021
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.3.4
.\"  Language: English
.\"
.TH "ZMQ_MSG_GET" "3" "01/17/2021" "0MQ 4\&.3\&.4" "0MQ Manual"
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.nh
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.\" * MAIN CONTENT STARTS HERE *
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.SH "NAME"
zmq_msg_get \- get message property
.SH "SYNOPSIS"
.sp
\fBint zmq_msg_get (zmq_msg_t \fR\fB\fI*message\fR\fR\fB, int \fR\fB\fIproperty\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fIzmq_msg_get()\fR function shall return the value for the property specified by the \fIproperty\fR argument for the message pointed to by the \fImessage\fR argument\&.
.sp
The following properties can be retrieved with the \fIzmq_msg_get()\fR function:
.PP
\fBZMQ_MORE\fR
.RS 4
Indicates that there are more message frames to follow after the
\fImessage\fR\&.
.RE
.PP
\fBZMQ_SRCFD\fR
.RS 4
Returns the file descriptor of the socket the
\fImessage\fR
was read from\&. This allows application to retrieve the remote endpoint via
\fIgetpeername(2)\fR\&. Be aware that the respective socket might be closed already, reused even\&. Currently only implemented for TCP sockets\&.
.RE
.PP
\fBZMQ_SHARED\fR
.RS 4
Indicates that a message MAY share underlying storage with another copy of this message\&.
.RE
.SH "RETURN VALUE"
.sp
The \fIzmq_msg_get()\fR function shall return the value for the property 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
\fIproperty\fR
is unknown\&.
.RE
.SH "EXAMPLE"
.PP
\fBReceiving a multi-frame message\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
zmq_msg_t frame;
while (true) {
    //  Create an empty 0MQ message to hold the message frame
    int rc = zmq_msg_init (&frame);
    assert (rc == 0);
    //  Block until a message is available to be received from socket
    rc = zmq_msg_recv (socket, &frame, 0);
    assert (rc != \-1);
    if (zmq_msg_get (&frame, ZMQ_MORE))
        fprintf (stderr, "more\en");
    else {
        fprintf (stderr, "end\en");
        break;
    }
    zmq_msg_close (&frame);
}
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_msg_set\fR(3) \fBzmq_msg_init\fR(3) \fBzmq_msg_close\fR(3) \fBzmq\fR(7)
.SH "AUTHORS"
.sp
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[]\&.