redhat man page for gethostid

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

NAME
       gethostid, sethostid - get or set the unique identifier of the current host

SYNOPSIS
       #include <unistd.h>

       long gethostid(void);
       int sethostid(long hostid);

DESCRIPTION
       Get  or	set  a unique 32-bit identifier for the current machine.  The 32-bit identifier is intended to be unique among all UNIX systems in
       existence. This normally resembles the Internet address for the local machine, as returned by  gethostbyname(3),  and  thus  usually  never
       needs to be set.

       The sethostid call is restricted to the superuser.

       The hostid argument is stored in the file /etc/hostid.

RETURN VALUE
       gethostid returns the 32-bit identifier for the current host as set by sethostid(2).

CONFORMING TO
       4.2BSD.	 These	functions  were  dropped  in  4.4BSD.	POSIX.1  does not define these functions, but ISO/IEC 9945-1:1990 mentions them in
       B.4.4.1.  SVr4 includes gethostid but not sethostid.

FILES
       /etc/hostid

SEE ALSO
       hostid(1), gethostbyname(3)

Linux 0.99.13							    1993-11-29							      GETHOSTID(2)