---
name: "nng_msg_header"
section: "3"
platform: "linux"
package: "libnng-dev"
version: "1.10.1-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/nng_msg_header"
---

# nng\_msg\_header(3)

return message header

## NAME

nng\_msg\_header - return message header

## SYNOPSIS

```
#include <nng/nng.h>
void *nng_msg_header(nng_msg *msg);
```

## DESCRIPTION

The `nng_msg_header()` function returns a pointer to the start of the header content of the message *msg*.

**Note**\

The message header contains protocol-specific header content.  Most applications should not need to access this content, but it is available for raw mode sockets (set with the `NNG_OPT_RAW` option.)

**Note**\

The value returned by this is invalidated by a call to any of the functions that modify the message or the header content.

## RETURN VALUES

Pointer to start of message header.

## ERRORS

None.

## SEE ALSO

[nng\_msg\_alloc(3)](/nng_msg_alloc/3.md), [nng\_msg\_body(3)](/nng_msg_body/3.md), [nng\_msg\_free(3)](/nng_msg_free/3.md), [nng\_msg\_header\_append(3)](/nng_msg_header_append/3.md), [nng\_msg\_header\_chop(3)](/nng_msg_header_chop/3.md), [nng\_msg\_header\_insert(3)](/nng_msg_header_insert/3.md) [nng\_msg\_header\_len(3)](/nng_msg_header_len/3.md), [nng\_msg\_header\_trim(3)](/nng_msg_header_trim/3.md), [nng\_msg(5)](/nng_msg/5.md), [nng(7)](/nng/7.md)