GETDOMAINNAME(2)            Linux Programmer's Manual           GETDOMAINNAME(2)

       getdomainname, setdomainname - get/set NIS domain name

       #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:
           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)

       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).

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

       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.

       POSIX does not specify these calls.

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

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

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

       This page is part of release 5.13 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

Linux                              2021-03-22                   GETDOMAINNAME(2)