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::hostent;
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;
}
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
perl v5.10.0 2007-12-18 Net::hostent(3)
