freebsd man page for gethostname

GETHOSTNAME(3)						   BSD Library Functions Manual 					    GETHOSTNAME(3)

NAME
     gethostname, sethostname -- get/set name of current host

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <unistd.h>

     int
     gethostname(char *name, size_t namelen);

     int
     sethostname(const char *name, int namelen);

DESCRIPTION
     The gethostname() function returns the standard host name for the current processor, as previously set by sethostname().  The namelen argu-
     ment specifies the size of the name array.  The returned name is null-terminated unless insufficient space is provided.

     The sethostname() function sets the 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.

     Host names are limited to {HOST_NAME_MAX} characters, not including the trailing null, currently 255.

RETURN VALUES
     Upon successful completion, the value 0 is returned; 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 argument gave an invalid address.

     [ENAMETOOLONG]	The current host name is longer than namelen.  (For gethostname() only.)

     [EPERM]		The caller tried to set the host name and was not the super-user.

SEE ALSO
     sysconf(3), sysctl(3)

STANDARDS
     The gethostname() function conforms to IEEE Std 1003.1-2001 (``POSIX.1'').  Callers should be aware that {HOST_NAME_MAX} may be variable or
     infinite, but is guaranteed to be no less than {_POSIX_HOST_NAME_MAX}.  On older systems, this limit was defined in the non-standard header
     <sys/param.h> as MAXHOSTNAMELEN, and counted the terminating null.  The sethostname() function and the error returns for gethostname() are
     not standardized.

HISTORY
     The gethostname() function appeared in 4.2BSD.  The namelen argument to gethostname() was changed to size_t in FreeBSD 5.2 for alignment with
     IEEE Std 1003.1-2001 (``POSIX.1'').

BSD
								  August 18, 2003							       BSD