Net::hostent

Net::hostent(3)        Perl Programmers Reference Guide        Net::hostent(3)



NAME
       Net::hostent - by-name interface to Perl's built-in gethost*() func-
       tions

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 simi-
       larly 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 names-
       pace 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()" cor-
       responds 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 mod-
       ule to build a struct-like class, you shouldn't rely upon this.

AUTHOR
       Tom Christiansen



perl v5.8.6                       2001-09-21                   Net::hostent(3)