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

# [NAME](#NAME)

zmq\_msg\_size - retrieve message content size in bytes

# [SYNOPSIS](#SYNOPSIS)

**size\_t zmq\_msg\_size (zmq\_msg\_t \*msg);**

# [DESCRIPTION](#DESCRIPTION)

The *zmq\_msg\_size()* function shall return the size in bytes of the content of the message object referenced by *msg*.

**Caution**

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

# [RETURN VALUE](#RETURN_VALUE)

Upon successful completion, *zmq\_msg\_size()* shall return the size of the message content in bytes.

# [ERRORS](#ERRORS)

No errors are defined.

# [SEE ALSO](#SEE_ALSO)

[**zmq\_msg\_data**(3)](/man/os/zeromq/zmq_msg_data.3) [**zmq\_msg\_init**(3)](/man/os/zeromq/zmq_msg_init.3) [**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**(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**.

10/24/2026 0MQ 4.3.5

---

Document: zmq_msg_size(3) from zeromq 4.3.5-r14 (Chainguard OS)
Source: https://github.com/zeromq/libzmq