gistfile1.txt

#! perl
use strict;
use warnings;
use DBI;
use Sys::SigAction qw(set_sig_handler);

my $h = set_sig_handler(
    'ALRM',
    sub {
        print "fire\n";
    },
);

if ( fork ) {
    sleep(1);
#    $SIG{ALRM} = sub { print "fire\n"; };
    alarm(3);
    my $dbh = DBI->connect('dbi:SQLite:./hoge.db', '', '');
    $dbh->do('select * from user');
    wait;
} else {
    open my $fh, './hoge.db';
    flock($fh, 6);
    sleep(10);
    close $fh;
}