Net::hostent(3) Perl Programmers Reference Guide Net::hostent(3)NAMENet::hostent - by-name interface to Perl's built-in
gethost*() functions
SYNOPSIS
use Net::hostnet;
DESCRIPTION
This module's default exports override the core
gethostbyname() and gethostbyaddr() functions, replacing
them with versions that return "Net::hostent" objects.
This object has methods that return the similarly named
structure field name from the C's hostent structure from
netdb.h; namely name, aliases, addrtype, length, and
addr_list. The aliases and addr_list methods return array
reference, the rest scalars. The addr method is
equivalent to the zeroth element in the addr_list array
reference.
You may also import all the structure fields directly into
your namespace as regular variables using the :FIELDS
import tag. (Note that this still overrides your core
functions.) Access these fields as variables named with a
preceding h_. Thus, $host_obj->name() corresponds to
$h_name if you import the fields. Array references are
available as regular array variables, so for example @{
$host_obj->aliases() } would be simply @h_aliases.
The gethost() function is a simple front-end that forwards
a numeric argument to gethostbyaddr() by way of
Socket::inet_aton, and the rest to gethostbyname().
To access this functionality without the core overrides,
pass the use an empty import list, and then access
function functions with their full qualified names. On
the other hand, the built-ins are still available via the
CORE:: pseudo-package.
EXAMPLES
use Net::hostent;
use Socket;
@ARGV = ('netscape.com') unless @ARGV;
for $host ( @ARGV ) {
unless ($h = gethost($host)) {
warn "$0: no such host: $host\n";
next;
}
16/Sep/1999 perl 5.005, patch 03 1
Net::hostent(3) Perl Programmers Reference Guide Net::hostent(3)
printf "\n%s is %s%s\n",
$host,
lc($h->name) eq lc($host) ? "" : "*really* ",
$h->name;
print "\taliases are ", join(", ", @{$h->aliases}), "\n"
if @{$h->aliases};
if ( @{$h->addr_list} > 1 ) {
my $i;
for $addr ( @{$h->addr_list} ) {
printf "\taddr #%d is [%s]\n", $i++, inet_ntoa($addr);
}
} else {
printf "\taddress is [%s]\n", inet_ntoa($h->addr);
}
if ($h = gethostbyaddr($h->addr)) {
if (lc($h->name) ne lc($host)) {
printf "\tThat addr reverses to host %s!\n", $h->name;
$host = $h->name;
redo;
}
}
}
NOTE
While this class is currently implemented using the
Class::Struct module to build a struct-like class, you
shouldn't rely upon this.
AUTHOR
Tom Christiansen
16/Sep/1999 perl 5.005, patch 03 2