usr/man/man2/gethostid.2

.TH GETHOSTID 2 "12 February 1983"
.UC 4
.SH NAME
gethostid, sethostid \- get/set unique identifier of current host
.SH SYNOPSIS
.nf
.ft B
hostid = gethostid()
int hostid;
.PP
.ft B
sethostid(hostid)
int hostid;
.fi
.SH DESCRIPTION
.I Sethostid
establishes a 32-bit identifier for the
current processor which is intended to be unique among all
UNIX systems in existence.  This is normally a DARPA Internet
address for the local machine.  This call is allowed only to the
super-user and is normally performed at boot time.
.PP
.I Gethostid
returns the 32-bit identifier for the current processor.
.SH SEE ALSO
hostid(1), gethostname(2)
.SH BUGS
32 bits for the identifier is too small.