从osCommerce找出来的缓存函数

<?php


////
//! Write out serialized data.
//  write_cache uses serialize() to store $var in $filename.
//  $var      -  The variable to be written out.
//  $filename -  The name of the file to write to.
  function write_cache(&$var, $filename) {
    $filename =  $filename;
    $success = false;

// try to open the file
    if ($fp = @fopen($filename, 'w')) {
// obtain a file lock to stop corruptions occuring
      flock($fp, 2); // LOCK_EX
// write serialized data
      fputs($fp, serialize($var));
// release the file lock
      flock($fp, 3); // LOCK_UN
      fclose($fp);
      $success = true;
    }

    return $success;
  }

////
//! Read in seralized data.
//  read_cache reads the serialized data in $filename and
//  fills $var using unserialize().
//  $var      -  The variable to be filled.
//  $filename -  The name of the file to read.
  function read_cache(&$var, $filename, $auto_expire = false){
    $filename = $filename;
    $success = false;

    if (($auto_expire == true) && file_exists($filename)) {
      $now = time();
      $filetime = filemtime($filename);
      $difference = $now - $filetime;

      if ($difference >= $auto_expire) {
        return false;
      }
    }

// try to open file
    if ($fp = @fopen($filename, 'r')) {
// read in serialized data
      $szdata = fread($fp, filesize($filename));
      fclose($fp);
// unserialze the data
      $var = unserialize($szdata);

      $success = true;
    }

    return $success;
  }


?>

示例:

<?php

read_cache($array,'cache.cache');
echo count($array);


$array = array();



$array[] = '1';
$array[] = '2';
$array[] = '3';

write_cache($array,'cache.cache');
?>