Net::servent(3p) Perl Programmers Reference Guide Net::servent(3p) #
Net::servent(3p) Perl Programmers Reference Guide Net::servent(3p)
NNAAMMEE #
Net::servent - by-name interface to Perl's built-in getserv*() functions
SSYYNNOOPPSSIISS #
use Net::servent;
$s = getservbyname(shift || 'ftp') || die "no service";
printf "port for %s is %s, aliases are %s\n",
$s->name, $s->port, "@{$s->aliases}";
use Net::servent qw(:FIELDS);
getservbyname(shift || 'ftp') || die "no service";
print "port for $s_name is $s_port, aliases are @s_aliases\n";
DDEESSCCRRIIPPTTIIOONN #
This module's default exports override the core ggeettsseerrvveenntt(()),
ggeettsseerrvvbbyynnaammee(()), and ggeettnneettbbyyppoorrtt(()) functions, replacing them with
versions that return "Net::servent" objects. They take default second
arguments of "tcp". This object has methods that return the similarly
named structure field name from the C's servent structure from _n_e_t_d_b_._h;
namely name, aliases, port, and proto. The aliases method returns an
array reference, the rest scalars.
You may also import all the structure fields directly into your namespace
as regular variables using the :FIELDS import tag. (Note that this still
overrides your core functions.) Access these fields as variables named
with a preceding "s_". Thus, "$serv_obj->name()" corresponds to $s_name
if you import the fields. Array references are available as regular
array variables, so for example "@{ $serv_obj->aliases()}" would be
simply @s_aliases.
The ggeettsseerrvv(()) function is a simple front-end that forwards a numeric
argument to ggeettsseerrvvbbyyppoorrtt(()), and the rest to ggeettsseerrvvbbyynnaammee(()).
To access this functionality without the core overrides, pass the "use"
an empty import list, and then access function functions with their full
qualified names. On the other hand, the built-ins are still available
via the "CORE::" pseudo-package.
EEXXAAMMPPLLEESS #
use Net::servent qw(:FIELDS);
while (@ARGV) {
my ($service, $proto) = ((split m!/!, shift), 'tcp');
my $valet = getserv($service, $proto);
unless ($valet) {
warn "$0: No service: $service/$proto\n"
next;
}
printf "service $service/$proto is port %d\n", $valet->port;
print "alias are @s_aliases\n" if @s_aliases;
}
NNOOTTEE #
While this class is currently implemented using the Class::Struct module
to build a struct-like class, you shouldn't rely upon this.
AAUUTTHHOORR #
Tom Christiansen
perl v5.36.3 2019-02-13 Net::servent(3p)