Net::hostent - by-name interface to Perl's built-in gethost*() functions
use Net::hostnet;
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() funtion 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.
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;
}
}
}
While this class is currently implemented using the Class::Struct module to build a struct-like class, you shouldn't rely upon this.
Tom Christiansen
If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.