Net::servent - by-name interface to Perl's built-in getserv*() functions
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";
This module's default exports override the core
getservent(),
getservbyname(), and
getnetbyport() 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
netdb.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
n_. Thus, $serv_obj->name() corresponds to $s_name if you import the fields. Array
references are available as regular array variables, so for example @{ $serv_obj->aliases()
} would be simply @s_aliases.
The
getserv() function is a simple front-end that forwards a numeric argument to
getservbyport(), and the rest to
getservbyname().
To access this functionality without the core overrides, pass the use an empty import list, and then access function functions with their full
qualified names. On the other hand, the built-ins are still available via
the CORE:: pseudo-package.
use Net::servent qw(:FIELDS);
while (@ARGV) {
my ($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;
}
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
If rather than formatting bugs, you encounter substantive content errors in these documents, such as mistakes in the explanations or code, please use the perlbug utility included with the Perl distribution.