use strict;
use warnings;
$|++; # make buffer 1 (error happens with or without this)
open LOG,">foo.log" or die "can't open foo.log: $!";
while (1) {
  print LOG (localtime).": something\n";
  sleep(30); # if I comment this, print works
}

##</code><code>##

use strict;
use warnings;
$|++; # make buffer 1 (error happens with or without this)
open LOG,">foo.log" or die "can't open foo.log: $!";
for (my $t=0;$t<3;$t++) {
  print LOG (localtime).": something\n";
  sleep(30);
}
close LOG or die "can't close log: $!";