zmq_msg_get(3)
ØMQ Manual - ØMQ/4.2.2
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 ØMQ 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); }
See also
zmq_msg_set(3) zmq_msg_init(3) zmq_msg_close(3) zmq(7)
Authors
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