package Net::protoent;use strict;BEGIN {     use Exporter   ();    use vars       qw(@EXPORT @EXPORT_OK %EXPORT_TAGS);    @EXPORT      = qw(getprotobyname getprotobynumber getprotoent);    @EXPORT_OK   = qw( $p_name @p_aliases $p_proto );    %EXPORT_TAGS = ( FIELDS => [ @EXPORT_OK, @EXPORT ] );}use vars      @EXPORT_OK;# Class::Struct forbids use of @ISAsub import { goto &Exporter::import }use Class::Struct qw(struct);struct 'Net::protoent' => [   name		=> '$',   aliases	=> '@',   proto	=> '$',];sub populate (@) {    return unless @_;    my $pob = new();    $p_name 	 =    $pob->[0]     	     = $_[0];    @p_aliases	 = @{ $pob->[1] } = split ' ', $_[1];    $p_proto	 =    $pob->[2] 	     = $_[2];    return $pob;} sub getprotoent      ( )  { populate(CORE::getprotoent()) } sub getprotobyname   ($)  { populate(CORE::getprotobyname(shift)) } sub getprotobynumber ($)  { populate(CORE::getprotobynumber(shift)) } sub getproto ($;$) {    no strict 'refs';    return &{'getprotoby' . ($_[0]=~/^\d+$/ ? 'number' : 'name')}(@_);}1;__END__=head1 NAMENet::protoent - by-name interface to Perl's built-in getproto*() functions=head1 SYNOPSIS use Net::protoent; $p = getprotobyname(shift || 'tcp') || die "no proto"; printf "proto for %s is %d, aliases are %s\n",    $p->name, $p->proto, "@{$p->aliases}"; use Net::protoent qw(:FIELDS); getprotobyname(shift || 'tcp') || die "no proto"; print "proto for $p_name is $p_proto, aliases are @p_aliases\n";=head1 DESCRIPTIONThis module's default exports override the core getprotoent(),getprotobyname(), and getnetbyport() functions, replacing them withversions that return "Net::protoent" objects.  They take defaultsecond arguments of "tcp".  This object has methods that return thesimilarly named structure field name from the C's protoent structurefrom F<netdb.h>; namely name, aliases, and proto.  The aliases methodreturns an array reference, the rest scalars.You may also import all the structure fields directly into your namespaceas regular variables using the :FIELDS import tag.  (Note that this stilloverrides your core functions.)  Access these fields as variables namedwith a preceding C<p_>.  Thus, C<$proto_obj-E<gt>name()> corresponds to$p_name if you import the fields.  Array references are available asregular array variables, so for example C<@{ $proto_obj-E<gt>aliases()}> would be simply @p_aliases.The getproto() function is a simple front-end that forwards a numericargument to getprotobyport(), and the rest to getprotobyname().To access this functionality without the core overrides,pass the C<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 C<CORE::> pseudo-package.=head1 NOTEWhile this class is currently implemented using the Class::Structmodule to build a struct-like class, you shouldn't rely upon this.=head1 AUTHORTom Christiansen