phpでlockする

lock.php

<?php
function lock($lockFileName, $fuc) {
  if(!file_exists($lockFileName)) {
    file_put_contents($lockFileName, '');
  }
  $lock_fp = fopen($lockFileName ,"w");
  flock($lock_fp, LOCK_EX);

  try {
    return $fuc();
  } finally {
    fclose($lock_fp);
  }
}

// USAGE
// $count = 0;
// while(true) {
//   lock('locktest', function() use (&$count) {
//     print($count++ . "\n");
//     sleep(1);
//   });
// }