Net::netent - phpMan

NAME
    Net::netent - by-name interface to Perl's built-in getnet*() functions

SYNOPSIS
     use Net::netent qw(:FIELDS);
     getnetbyname("loopback")               or die "bad net";
     printf "%s is %08X\n", $n_name, $n_net;

     use Net::netent;

     $n = getnetbyname("loopback")          or die "bad net";
     { # there's gotta be a better way, eh?
         @bytes = unpack("C4", pack("N", $n->net));
         shift @bytes while @bytes && $bytes[0] == 0;
     }
     printf "%s is %08X [%d.%d.%d.%d]\n", $n->name, $n->net, @bytes;

DESCRIPTION
    This module's default exports override the core getnetbyname() and
    getnetbyaddr() functions, replacing them with versions that return
    "Net::netent" objects. This object has methods that return the similarly
    named structure field name from the C's netent structure from netdb.h;
    namely name, aliases, addrtype, and net. The aliases method returns an
    array reference, the rest scalars.

    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 "n_". Thus, "$net_obj->name()"
    corresponds to $n_name if you import the fields. Array references are
    available as regular array variables, so for example "@{
    $net_obj->aliases() }" would be simply @n_aliases.

    The getnet() function is a simple front-end that forwards a numeric
    argument to getnetbyaddr(), and the rest to getnetbyname().

    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
    The getnet() functions do this in the Perl core:

        sv_setiv(sv, (I32)nent->n_net);

    The gethost() functions do this in the Perl core:

        sv_setpvn(sv, hent->h_addr, len);

    That means that the address comes back in binary for the host functions,
    and as a regular perl integer for the net ones. This seems a bug, but
    here's how to deal with it:

     use strict;
     use Socket;
     use Net::netent;

     @ARGV = ('loopback') unless @ARGV;

     my($n, $net);

     for $net ( @ARGV ) {

         unless ($n = getnetbyname($net)) {
            warn "$0: no such net: $net\n";
            next;
         }

         printf "\n%s is %s%s\n",
                $net,
                lc($n->name) eq lc($net) ? "" : "*really* ",
                $n->name;

         print "\taliases are ", join(", ", @{$n->aliases}), "\n"
                    if @{$n->aliases};

         # this is stupid; first, why is this not in binary?
         # second, why am i going through these convolutions
         # to make it looks right
         {
            my @a = unpack("C4", pack("N", $n->net));
            shift @a while @a && $a[0] == 0;
            printf "\taddr is %s [%d.%d.%d.%d]\n", $n->net, @a;
         }

         if ($n = getnetbyaddr($n->net)) {
            if (lc($n->name) ne lc($net)) {
                printf "\tThat addr reverses to net %s!\n", $n->name;
                $net = $n->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

Generated by phpMan Author: Che Dong On Apache Under GNU General Public License - MarkDown Format
2026-05-21 22:10 @216.73.216.105 CrawledBy Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; ClaudeBot/1.0; +claudebot@anthropic.com)