getdomainname(2)                                        System Calls Manual                                        getdomainname(2)

NAME
       getdomainname, setdomainname - get/set NIS domain name

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #include <unistd.h>

       int getdomainname(char *name, size_t len);
       int setdomainname(const char *name, size_t len);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getdomainname(), setdomainname():
           Since glibc 2.21:
               _DEFAULT_SOURCE
           In glibc 2.19 and 2.20:
               _DEFAULT_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)
           Up to and including glibc 2.19:
               _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500)

DESCRIPTION
       These functions are used to access or to change the NIS domain name of the host system.  More precisely, they operate on the
       NIS domain name associated with the calling process's UTS namespace.

       setdomainname() sets the domain name to the value given in the character array name.  The len argument specifies the  number
       of bytes in name.  (Thus, name does not require a terminating null byte.)

       getdomainname()  returns  the  null-terminated domain name in the character array name, which has a length of len bytes.  If
       the null-terminated domain name requires more than len bytes, getdomainname() returns the first len bytes (glibc)  or  gives
       an error (libc).

RETURN VALUE
       On success, zero is returned.  On error, -1 is returned, and errno is set to indicate the error.

ERRORS
       setdomainname() can fail with the following errors:

       EFAULT name pointed outside of user address space.

       EINVAL len was negative or too large.

       EPERM  The  caller  did  not  have the CAP_SYS_ADMIN capability in the user namespace associated with its UTS namespace (see
              namespaces(7)).

       getdomainname() can fail with the following errors:

       EINVAL For getdomainname() under libc: name is NULL or name is longer than len bytes.

STANDARDS
       POSIX does not specify these calls.

NOTES
       Since Linux 1.0, the limit on the length of a domain name, including the terminating null byte, is 64 bytes.  In older  ker‐
       nels, it was 8 bytes.

       On  most  Linux architectures (including x86), there is no getdomainname() system call; instead, glibc implements getdomain‐
       name() as a library function that returns a copy of the domainname field returned from a call to uname(2).

SEE ALSO
       gethostname(2), sethostname(2), uname(2), uts_namespaces(7)

Linux man-pages 6.03                                         2022-10-30                                            getdomainname(2)