ZMQ_MSG_GET - Online Linux Manual Page

Section : 3
Updated : 01/21/2023
Source : 0MQ 4.3.4
Note : 0MQ Manual

NAME

zmq_msg_get − get message property

SYNOPSIS

int zmq_msg_get (zmq_msg_t

*message

, int

property

);

DESCRIPTION

The zmq_msg_get(

)

function shall return the value for the property specified by the

property

argument for the message pointed to by the

message

argument. The following properties can be retrieved with the

zmq_msg_get(

)

function:

ZMQ_MORE

Indicates that there are more message frames to follow after the message

ZMQ_SRCFD

Returns the file descriptor of the socket the message

was read from. This allows application to retrieve the remote endpoint via

getpeername(2)

. Be aware that the respective socket might be closed already, reused even. Currently only implemented for TCP sockets.

ZMQ_SHARED

Indicates that a message MAY share underlying storage with another copy of this message.

RETURN VALUE

The zmq_msg_get(

)

function shall return the value for the property if successful. Otherwise it shall return −1 and set

errno

to one of the values defined below.

ERRORS

EINVAL

The requested property

is unknown.

EXAMPLE

Receiving a multi-frame message

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\n"); else { fprintf (stderr, "end\n"); break; } zmq_msg_close (&frame); }