Net::hostent(3) Perl Programmers Reference Guide Net::hostent(3)NAMENet::hostent - by-name interface to Perl's built-in geth
ost*() functions
SYNOPSIS
use Net::hostnet;
DESCRIPTION
This module's default exports override the core gethostby_
name() 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 func
tion 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;
}
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
2001-02-22 perl v5.6.1 Net::hostent(3)
