perl-alarm-lexical-file-handle

use feature qw(say);
use strict;
use warnings;
use POSIX ":sys_wait_h";

local $SIG{ALRM} = sub { die "timed out\n"; };
my $pid;
my $start_time = time;
#my $fh2;
eval {
    alarm 5;
    #$pid = open $fh2, '-|', "sleep", 10;
    $pid = open my $fh, '-|', "sleep", 10;
    #$pid = open my $fh, "sleep 10|";
    #$pid = open FH, "sleep 10|";
    #$pid = open FH, '-|', "sleep", 10;
    say "reading line from child..";
    #my $line = <$fh2>;  # hangs here for 10 seconds..
    my $line = <$fh>;
    #my $line = <FH>;
    #close $fh2;
    #close $fh;
    #close FH;
    say "end of eval..";
    alarm 0;
};
say $@ if $@;
say "done. elapsed = ", time - $start_time;
if ( $pid ) {
    say "PID = $pid";
    my $kid = waitpid $pid, WNOHANG;
    say "waitpid returned $kid";
    if ($kid == -1) {
        say "child does not exist";
    }
    if ($kid == 0) {
        say "Killing child $pid";
        kill 'KILL', $pid;
        say "Done.";
    }
}
else {
    say "No child started..";
}