Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #633
Difficulty: Medium
The touch and gesture features of the iPhone are based on technology originally developed by FingerWorks.
True or False?
Linux & Unix Commands - Search Man Pages

gethostid(3c) [sunos man page]

gethostid(3C)						   Standard C Library Functions 					     gethostid(3C)

NAME
gethostid - get an identifier for the current host SYNOPSIS
#include <unistd.h> long gethostid(void); DESCRIPTION
The gethostid() function returns the 32-bit identifier for the current host. This identifier is taken from the CPU board's ID PROM. It is not guaranteed to be unique. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
hostid(1), sysinfo(2), attributes(5), standards(5) SunOS 5.10 24 Jul 2002 gethostid(3C)

Check Out this Related Man Page

GETHOSTID(3)						     Linux Programmer's Manual						      GETHOSTID(3)

NAME
gethostid, sethostid - get or set the unique identifier of the current host SYNOPSIS
#include <unistd.h> long gethostid(void); int sethostid(long hostid); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): gethostid() _BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED sethostid(): _BSD_SOURCE || (_XOPEN_SOURCE && _XOPEN_SOURCE < 500) DESCRIPTION
gethostid() and sethostid() respectively 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 geth- ostbyname(3), and thus usually never needs to be set. The sethostid() call is restricted to the superuser. RETURN VALUE
gethostid() returns the 32-bit identifier for the current host as set by sethostid(). On success, sethostid() returns 0; on error, -1 is returned, and errno is set to indicate the error. ERRORS
sethostid() can fail with the following errors: EACCES The caller did not have permission to write to the file used to store the host ID. EPERM The calling process's effective user or group ID is not the same as its corresponding real ID. 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, the hostid is stored in the file /etc/hostid. (In glibc versions before 2.2, the file /var/adm/hostid was used.) In the glibc implementation, if gethostid() cannot open the file containing the host ID, then it obtains the hostname using gethostname(2), passes that hostname 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.) BUGS
It is impossible to ensure that the identifier is globally unique. SEE ALSO
hostid(1), gethostbyname(3) COLOPHON
This page is part of release 3.27 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/. Linux 2010-09-20 GETHOSTID(3)

Featured Tech Videos