---
name: "zmq_msg_init_size"
section: "3"
platform: "linux"
package: "zeromq"
version: "4.3.5-3"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zmq_msg_init_size"
---

# zmq\_msg\_init\_size(3)

initialise 0MQ message of a specified size

## NAME

zmq\_msg\_init\_size - initialise 0MQ message of a specified size

## SYNOPSIS

**int zmq\_msg\_init\_size (zmq\_msg\_t** *\*msg***, size\_t** *size***);**

## DESCRIPTION

The *zmq\_msg\_init\_size()* function shall allocate any resources required to store a message *size* bytes long and initialise the message object referenced by *msg* to represent the newly allocated message.

The implementation shall choose whether to store message content on the stack (small messages) or on the heap (large messages). For performance reasons *zmq\_msg\_init\_size()* shall not clear the message data.

**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

The *zmq\_msg\_init\_size()* function shall return zero if successful. Otherwise it shall return -1 and set *errno* to one of the values defined below.

## ERRORS

**ENOMEM**

Insufficient storage space is available.

## SEE ALSO

[**zmq\_msg\_init\_data**(3)](/zmq_msg_init_data/3.md) [**zmq\_msg\_init\_buffer**(3)](/zmq_msg_init_buffer/3.md) [**zmq\_msg\_init**(3)](/zmq_msg_init/3.md) [**zmq\_msg\_close**(3)](/zmq_msg_close/3.md) [**zmq\_msg\_data**(3)](/zmq_msg_data/3.md) [**zmq\_msg\_size**(3)](/zmq_msg_size/3.md) [**zmq**(7)](/zmq/7.md)

## 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**.