Provided by:
manpages-dev_2.17-1_all 
NAME
gethostname, sethostname - get/set host name
SYNOPSIS
#include <unistd.h>
int gethostname(char *name, size_t len);
int sethostname(const char *name, size_t len);
DESCRIPTION
These functions are used to access or to change the host name of the
current processor. The gethostname() function returns a NUL-terminated
hostname (set earlier by sethostname()) in the array name that has a
length of len bytes. In case the NUL-terminated hostname does not fit,
no error is returned, but the hostname is truncated. It is unspecified
whether the truncated hostname will be NUL-terminated.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is
set appropriately.
ERRORS
EFAULT name is an invalid address.
EINVAL len is negative or, for sethostname(), len is larger than the
maximum allowed size, or, for gethostname() on Linux/i386, len
is smaller than the actual size. (In this last case glibc 2.1
uses ENAMETOOLONG.)
EPERM For sethostname(), the caller did not have the CAP_SYS_ADMIN
capability.
CONFORMING TO
SVr4, 4.4BSD (this function first appeared in 4.2BSD). POSIX
1003.1-2001 specifies gethostname() but not sethostname().
BUGS
For many Linux kernel / libc combinations gethostname() will return an
error instead of returning a truncated hostname.
NOTES
SUSv2 guarantees that ‘Host names are limited to 255 bytes’. POSIX
1003.1-2001 guarantees that ‘Host names (not including the terminating
NUL) are limited to HOST_NAME_MAX bytes’.
SEE ALSO
getdomainname(2), setdomainname(2), uname(2)