---
name: "getdomainname"
section: "3"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["freebsd", "macos"]
url: "https://new.carta.tech/getdomainname/3"
---

# getdomainname(3)

get/set NIS domain name of current host

## NAME

**getdomainname**, **setdomainname** – get/set NIS domain name of current host

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<unistd.h\>**

*int*\

**getdomainname**(*char \*name*, *int namelen*);

*int*\

**setdomainname**(*const char \*name*, *int namelen*);

## DESCRIPTION

**Getdomainname**() returns the standard NIS domain name for the current host, as previously set by **setdomainname**(). The parameter *namelen* specifies the size of the *name* array.  The returned name is null-terminated unless insufficient space is provided.

**Setdomainname**() sets the NIS domain name of the host machine to be *name*, which has length *namelen*. This call is restricted to the super-user and is normally used only when the system is bootstrapped.

## RETURN VALUES

The **getdomainname()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## ERRORS

The following errors may be returned by these calls:

- \[EFAULT\]

  The *name* or *namelen* parameter gave an invalid address.

- \[EPERM\]

  The caller tried to set the hostname and was not the super-user.

## SEE ALSO

[gethostid(3)](/gethostid/3.md), [gethostname(3)](/gethostname/3.md), [sysctl(3)](/sysctl/3.md)

## BUGS

Domain names are limited to MAXHOSTNAMELEN (from ⟨*sys/param.h*⟩) characters, currently 256.

## HISTORY

The **getdomainname**() function call appeared in 4.2BSD.