use strict;
use warnings;
use IO::Socket::INET;

my $srv = IO::Socket::INET->new(
    LocalAddr => '127.0.0.1',
    LocalPort => 7777,
    ReuseAddr => 1,
    Listen    => 1,
) or die $!;

my $sock = IO::Socket::INET->new(
    PeerAddr => '127.0.0.1',
    PeerPort => 7777,
) or die $!;
my $cli = $srv->accept or die $!;

my $sock2 = IO::Socket::INET->new(
    PeerAddr => '127.0.0.1',
    PeerPort => 7777,
) or die $!;
my $cli2 = $srv->accept or die $!;

local $SIG{ALRM} = sub { $sock->send( "hi\n", 0 ); };

alarm 2;

my $res;
use Data::Dumper;
$res = $sock2->recv( my $buf, 1024 ) or die Dumper [ $res, $!, 0 + $!, ];
__END__
$VAR1 = [
          undef,
          '',
          '0'
        ];