Name
gethostid, sethostid — get or set the unique identifier of the current host
Synopsis
#include <unistd.h>
long
gethostid( |
void); |
int
sethostid( |
long | hostid); |
![[Note]](../stylesheet/note.png) |
Note | ||
|---|---|---|---|
|
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.
CONFORMING TO
4.2BSD; these functions were dropped in 4.4BSD. SVr4
includes gethostid() but not
sethostid(). POSIX.1-2001
specifies gethostid() but not
sethostid().
NOTES
In the glibc implementation, if gethostid() cannot open /etc/hostid, then it obtains the host name
using gethostname(2), passes that
host name to gethostbyname_r(3) in order
to obtain the host's IPv4 address, and returns a value
obtained by bit-twiddling the IPv4 address. (This value may
not be unique.)
COLOPHON
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
|
Copyright 1993 Rickard E. Faith (faithcs.unc.edu) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. Updated with additions from Mitchum DSouza <m.dsouzamrc-apu.cam.ac.uk> Portions Copyright 1993 Mitchum DSouza <m.dsouzamrc-apu.cam.ac.uk> Modified Tue Oct 22 00:22:35 EDT 1996 by Eric S. Raymond <esrthyrsus.com> |