zmq_recv(3)

SYNOPSIS

int zmq_recv (void *socket, void *buf, size_t len, int flags);

DESCRIPTION

The zmq_recv() function shall receive a message from the socket referenced +by the socket argument and store it in the buffer referenced by the buf +argument. Any bytes exceeding the length specified by the len argument shall +be truncated. If there are no messages available on the specified socket +the zmq_recv() function shall block until the request can be satisfied. +The flags argument is a combination of the flags defined below:

+ZMQ_DONTWAIT +: +
+Specifies that the operation should be performed in non-blocking mode. If there +are no messages available on the specified socket, the zmq_recv() +function shall fail with errno set to EAGAIN. +
+

Multi-part messages

A ØMQ message is composed of 1 or more message parts. ØMQ ensures atomic +delivery of messages: peers shall receive either all message parts of a +message or none at all. The total number of message parts is unlimited except +by available memory.

An application that processes multi-part messages must use the ZMQ_RCVMORE +zmq_getsockopt(3) option after calling zmq_recv() to determine if +there are further parts to receive.

RETURN VALUE

The zmq_recv() function shall return number of bytes in the message +if successful. Note that the value can exceed the value of the len parameter +in case the message was truncated. If not successful the function shall return +-1 and set errno to one of the values defined below.

ERRORS

+EAGAIN +: +
+Non-blocking mode was requested and no messages are available at the moment. +
+
+ENOTSUP +: +
+The zmq_recv() operation is not supported by this socket type. +
+
+EFSM +: +
+The zmq_recv() 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 +messaging patterns section of zmq_socket(3) for more information. +
+
+ETERM +: +
+The ØMQ context associated with the specified socket was terminated. +
+
+ENOTSOCK +: +
+The provided socket was invalid. +
+
+EINTR +: +
+The operation was interrupted by delivery of a signal before a message was +available. +
+

EXAMPLE

Receiving a message from a socket

char buf [256];
+nbytes = zmq_recv (socket, buf, 256, 0);
+assert (nbytes != -1);

AUTHORS

This page was written by the ØMQ community. To make a change please +read the ØMQ Contribution Policy at http://www.zeromq.org/docs:contributing.

+zmq_recv(3) Manual Page +

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