in reply to perl and getaddrinfo API

Hello swissknife,

If you display the contents of $pip using Data::Dump, say, you’ll see that it actually contains four bytes:

#! perl
use strict;
use warnings;
use Socket;
use Data::Dump;

my $server = shift @ARGV;
my $pip = gethostbyname($server);
dd $pip;
my $IP_add = inet_ntoa($pip);
print $IP_add;

[download]

Output:

21:17 >perl 1602_SoPW.pl perlmonks.pair.com
"\xD1\xC5{\x99"
209.197.123.153
21:17 >

[download]

If these bytes don’t appear when you print $pip, that’s likely because they happen to be unprintable.

BTW, the documentation for Socket mentions that gethostbyname is a legacy subroutine.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

Replies are listed 'Best First'.
Re^2: perl and getaddrinfo API
by swissknife (Sexton) on Apr 20, 2016 at 12:28 UTC
    Thanks for pointing out to problem. about the legacy subroutine i tried the new codes. 
     use Socket qw(:addrinfo SOCK_RAW);

 my ($err, @res) = getaddrinfo($hostname, "", {socktype => SOCK_RAW});
 die "Cannot getaddrinfo - $err" if $err;

 while( my $ai = shift @res ) {
     my ($err, $ipaddr) = getnameinfo($ai->{addr}, NI_NUMERICHOST, NIx
+_NOSERV);
    die "Cannot getnameinfo - $err" if $err;

     print "$ipaddr\n";
 }

    [download]

    copied from http://perldoc.perl.org/Socket.html#(%24err%2c-%40result)-%3d-getaddrinfo-%24host%2c-%24service%2c-%5b%24hints%5d

    it gives me error "addrinfo not defined in %Socket::EXPORT_TAGS

    perl i am using is 5.8.4. is this because of perl version i am using? or it is something else?

[reply]
[d/l]

      Perl 5.8 is very old. Whether that’s the problem I don’t know; but when I add a line defining $hostname to the code you posted:

      #! perl
use strict;
use warnings;
use Socket qw(:addrinfo SOCK_RAW);

my $hostname = 'perlmonks.pair.com';

my ($err, @res) = getaddrinfo($hostname, "", { socktype => SOCK_RAW })
+;
die "Cannot getaddrinfo - $err" if $err;

while (my $ai = shift @res)
{
    my ($err, $ipaddr) = getnameinfo($ai->{addr}, NI_NUMERICHOST, NIx_
+NOSERV);
    die "Cannot getnameinfo - $err" if $err;

    print "$ipaddr\n";
}

      [download]

      it works correctly on my system:

      22:41 >perl 1602_SoPW.pl
209.197.123.153

22:42 >

      [download]

      (Windows 8.1 64-bit, Strawberry Perl 5.22.1, Socket v2.021.)

      Hope that helps,

      Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

[reply]
[d/l]
[select]

      Yes, the old Perl version is the problem. The core Socket module didn't start supporting IPv6 (and the address family independent routines get*info()) until at least 5.14 or so.

      Socket is now dual-lived so you can get the latest copy from CPAN, but not sure how a new version of Socket will work on such an old Perl.

      You could try Socket6 and / or Socket::GetAddrInfo. I've used in the past and the API was a bit different than the "standard" supplied directly in the new Socket module versions.

[reply]

In Section Seekers of Perl Wisdom