PHPの可変長パラメータ処理関数の詳細説明

function open_database($DB, $cache_size_or_values=null, $cache_size=null)
{
  switch (function_num_args())
  {
    case 1:
      $r = select_db($DB);
      break;
    case 2:
      $r = select_db($DB, $cache_size_or_values);
      break;
    case 3:
      $r = select_db($DB, $cache_size_or_values, $cache_size);
      break;
  }
  return is_resource($r);
}

<?php
  function some_func($a, $b)
  {
    for($i = 0; $i<func_num_args(); ++$i)
    {
      $param = func_get_arg($i);
      echo "the param is $param\n"
    }
  }
  some_func(1,3,5,7,9);
?>

<?php
  function some_other_func($a, $b)
  {
    $param = func_get_args();
    $param = join(", ", $param);  // 分解显示
    echo "the arglist is: $param\n";
  }
  some_other_func(1,3,5,7,9);
?>