Description

A C extension that provides hostname and IP address information
about the current host.

Synopsis

require 'sys/host'
include Sys

puts Host.hostname
puts Host.ip_addr

# For a multi-nic system
Host.ip_addr.each do |ip|
   puts ip
end

Constants

VERSION: Returns the current version number of this package (as a string)

Class Methods

Host.hostname: Returns the hostname of the current host. This may or not return the FQDN, depending on your system.
Host.ip_addr: Returns a list of IP addresses for the current host (yes, it is possible to have more than one).
Host.VERSION: Returns the current version number as a string. Be sure to use parens for this method call or you'll end up getting the *Ruby* version number.

Exception Classes

HostException < StandardError: This exception is raised if the gethostname() call returns a non-zero value. If you hit this error, you got big problems. This can be raised in either the hostname or ip_addr method.
HostAddressException < StandardError: This exception is raised if the gethostbyname() call returns a NULL hostent structure in the ip_addr method. That *probably* means the hostname hasn't been defined in /etc/hosts.

Notes

IPV6 is not supported (yet).

Future Plans

Add reentrant versions for other platforms.

Add support for IPV6.  This will be difficult unless I have access to a
system on an IPV6 network.  Any help on this front appreciated.

Questions

"This module doesn't do very much.  What's the point?" - I thought that
having to load the 'socket' module was overkill just to get the hostname.

"Why an extension?  Wouldn't it have been easier to just parse the output
of a system call?" - What fun would that be?  Seriously, I didn't want to
have to spawn a subprocess for this.  Besides, Perl has a Sys::Hostname
module, so I thought Ruby should have one, too.

Mine does more, though. :)

Known Bugs

Returning multiple ip addresses for multi-homed systems doesn't seem to
work properly.  Help appreciated

Acknowledgements

Thanks go to Mike Hall, Guy Decoux, and Matz for their help with
C extensions in general. :)

Thanks also go to Richard Stevens for his *awesome* Unix programming books.

Copyright

Copyright 2002-2003, Daniel J. Berger, djberg96@yahoo.com

All Rights Reserved. This module is free software. It may be used,
redistributed and/or modified under the same terms as Ruby itself.

Author

Daniel J. Berger
djberg96 at yahoo dot com
rubyhacker1 on IRC