Net::hostent(3p)Perl Programmers Reference Guide Net::hostent(3p)
Net::hostent - by-name interface to Perl's built-in gethost*() functions
use Net::hostent;
This module's default exports override the core gethost- byname() 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 ele- ment 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.
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; } perl v5.8.8 2005-02-05 1 Net::hostent(3p)Perl Programmers Reference Guide Net::hostent(3p) 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 perl v5.8.8 2005-02-05 2