From 02885230c0d31362dde4f4cf2669c1c4b67d7f51 Mon Sep 17 00:00:00 2001
From: Alex Sudakov <cygakob@gmail.com>
Date: Wed, 15 Nov 2017 00:24:11 -0600
Subject: [PATCH 1/2] prevent undef warning on the screen

---
 mytop | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mytop b/mytop
index fba27fd..38b4931 100755
--- a/mytop
+++ b/mytop
@@ -954,7 +954,8 @@ sub GetData()
         if ($is_ip and $config{resolve})
         {
             $thread->{Host} =~ s/:\d+$//;
-            my $host = gethostbyaddr(inet_aton($thread->{Host}), AF_INET);
+            # default host with digits => to prevent warnings on the screen
+            my $host = gethostbyaddr(inet_aton($thread->{Host}), AF_INET) // $thread->{Host};
             $host =~ s/^([^.]+).*/$1/;
             $thread->{Host} = $host;
         }

From 0bdf61de4af636c1111a433a7e47fd8a527e232b Mon Sep 17 00:00:00 2001
From: Alex Sudakov <cygakob@gmail.com>
Date: Wed, 15 Nov 2017 00:53:13 -0600
Subject: [PATCH 2/2] do not get part before dot for IP as for host, empty
 string fallback

---
 mytop | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/mytop b/mytop
index 38b4931..c22baa3 100755
--- a/mytop
+++ b/mytop
@@ -954,9 +954,15 @@ sub GetData()
         if ($is_ip and $config{resolve})
         {
             $thread->{Host} =~ s/:\d+$//;
-            # default host with digits => to prevent warnings on the screen
-            my $host = gethostbyaddr(inet_aton($thread->{Host}), AF_INET) // $thread->{Host};
-            $host =~ s/^([^.]+).*/$1/;
+            my $host = gethostbyaddr(inet_aton($thread->{Host}), AF_INET);
+            if(defined $host) {
+                $host =~ s/^([^.]+).*/$1/;
+            }
+            else {
+                # undef will garbage the screen
+                # fallback to IP or empty string
+                $host = $thread->{Host} // '';
+            }
             $thread->{Host} = $host;
         }