From 4153b41d3a22af7889edf72ae68838ccc3645e1d Mon Sep 17 00:00:00 2001
From: benrubson <6764151+benrubson@users.noreply.github.com>
Date: Thu, 5 Nov 2020 20:10:28 +0100
Subject: [PATCH] Get rid of alarm()

for better cross-platform compatibility
---
 lib/Net/NTP.pm | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/lib/Net/NTP.pm b/lib/Net/NTP.pm
index 59a5352..d302b78 100644
--- a/lib/Net/NTP.pm
+++ b/lib/Net/NTP.pm
@@ -171,14 +171,17 @@ sub get_ntp_response {
 
     ## receive with deadline
     my $data;
-    eval {
-        local $SIG{ALRM} = sub { die "Net::NTP timed out getting NTP packet\n"; };
-        alarm($TIMEOUT);
+    my $rin = '';
+    vec($rin, $sock->fileno(), 1) = 1;
+    my $rout = $rin;
+    select($rout, undef, undef, $TIMEOUT);
+    if (vec($rout, $sock->fileno(), 1)) {
         $sock->recv($data, 960)
-          or die "recv() failed: $!\n";
-        alarm(0);
-    };
-    alarm 0;
+            or die "recv() failed: $!\n";
+    }
+    else {
+        die "Net::NTP timed out getting NTP packet\n";
+    }
 
     my $rectime = time; # T4
     my $pkt = Net::NTP::Packet->decode($data, $xmttime, $rectime);