#!/usr/bin/perl

sub process_scheme{
    my ($cmd, $output_file) = @_;
    open (OUTPUT_FILE, ">", $output_file) || die "cannot open log file";
    my $scheme_pid = open (WORKER, "$cmd |") 
         || die "cannot pipe worker";
    my $str;
    while (1) {
        if (eof(WORKER)){    
            close WORKER;
            close OUTPUT;
            return 1;
        }

        eval{
            local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required
            alarm 1;
            $str = <WORKER>;
            alarm 0;
        };
        if ($@) {
            close OUTPUT_FILE;
            close WORKER;
            return 0;
        }

        print OUTPUT_FILE $str;
    }
}

my $code = '$|=1; my $t=2; for (1..100) { printf "%.1f\n", $_*$t; select undef,undef,undef,$t; }';
my $cmd  = "perl -e '$code'";
process_scheme($cmd, "test.out");