ZMQ\_MSG\_INIT(3) 0MQ Manual ZMQ\_MSG\_INIT(3)

# [NAME](#NAME)

zmq\_msg\_init - initialise empty 0MQ message

# [SYNOPSIS](#SYNOPSIS)

**int zmq\_msg\_init (zmq\_msg\_t \*msg);**

# [DESCRIPTION](#DESCRIPTION)

The *zmq\_msg\_init()* function shall initialise the message object referenced by *msg* to represent an empty message. This function is most useful when called before receiving a message with *zmq\_msg\_recv()*.

**Caution**

Never access *zmq\_msg\_t* members directly, instead always use the *zmq\_msg* family of functions.

**Caution**

The functions *zmq\_msg\_init()*, *zmq\_msg\_init\_data()*, *zmq\_msg\_init\_size()* and *zmq\_msg\_init\_buffer()* are mutually exclusive. Never initialise the same *zmq\_msg\_t* twice.

# [RETURN VALUE](#RETURN_VALUE)

The *zmq\_msg\_init()* function always returns zero.

# [ERRORS](#ERRORS)

No errors are defined.

# [EXAMPLE](#EXAMPLE)

**Receiving a message from a socket**.

```
zmq_msg_t msg;
rc = zmq_msg_init (&msg);
assert (rc == 0);
int nbytes = zmq_msg_recv (socket, &msg, 0);
assert (nbytes != -1);
```

# [SEE ALSO](#SEE_ALSO)

[**zmq\_msg\_init\_size**(3)](/man/os/zeromq/zmq_msg_init_size.3) [**zmq\_msg\_init\_buffer**(3)](/man/os/zeromq/zmq_msg_init_buffer.3) [**zmq\_msg\_init\_data**(3)](/man/os/zeromq/zmq_msg_init_data.3) [**zmq\_msg\_close**(3)](/man/os/zeromq/zmq_msg_close.3) [**zmq\_msg\_data**(3)](/man/os/zeromq/zmq_msg_data.3) [**zmq\_msg\_size**(3)](/man/os/zeromq/zmq_msg_size.3) [**zmq**(7)](/man/os/zeromq/zmq.7)

# [AUTHORS](#AUTHORS)

This page was written by the 0MQ community. To make a change please read the 0MQ Contribution Policy at **http://www.zeromq.org/docs:contributing**.

10/26/2026 0MQ 4.3.5

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Document: zmq_msg_init(3) from zeromq 4.3.5-r15 (Chainguard OS)
Source: https://github.com/zeromq/libzmq