<?php
if( !function_exists('memory_get_usage') )
{
   function memory_get_usage()
   {
       //If its Windows
       //Tested on Win XP Pro SP2. Should work on Win 2003 Server too
       //Doesn't work for 2000
       //If you need it to work for 2000 look at http://us2.php.net/manual/en/function.memory-get-usage.php#54642
       if ( substr(PHP_OS,0,3) == 'WIN')
       {
               if ( substr( PHP_OS, 0, 3 ) == 'WIN' )
               {
                   $output = array();
                   exec( 'tasklist /FI "PID eq ' . getmypid() . '" /FO LIST', $output );
      
                   return preg_replace( '/[\D]/', '', $output[5] ) * 1024;
               }
       }else
       {
           //We now assume the OS is UNIX
           //Tested on Mac OS X 10.4.6 and Linux Red Hat Enterprise 4
           //This should work on most UNIX systems
           $pid = getmypid();
           exec("ps -eo%mem,rss,pid | grep $pid", $output);
           $output = explode("  ", $output[0]);
           //rss is given in 1024 byte units
           return $output[1] * 1024;
       }
   }
}
$b=memory_get_usage();
$b=memory_get_usage();
$b=memory_get_usage();
$b=memory_get_usage();
$b=memory_get_usage();
$b=memory_get_usage();
//-------------
//Ignore that multiple loops
//Its only to have CLEAN memory_usage because of exec
$b=memory_get_usage();
function flood(){for($i=0;$i<1000;$i++)$a[$i]=new StdClass;} 
flood();
echo "Start:$b #1 Memory Usage:".number_format((memory_get_usage() - $b) / 1024, 2) . "KB\n";

flood();
echo "Start:$b #2 Memory Usage:".number_format((memory_get_usage() - $b) / 1024, 2) . "KB\n";

flood();
echo "Start:$b #3 Memory Usage:".number_format((memory_get_usage() - $b) / 1024, 2) . "KB\n";

flood();
echo "Start:$b #4 Memory Usage:".number_format((memory_get_usage() - $b) / 1024, 2) . "KB\n";

flood();
echo "Start:$b #5 Memory Usage:".number_format((memory_get_usage() - $b) / 1024, 2) . "KB\n";
/*
X:\>php -f mem.php
Start:13619200 #1 Memory Usage:128.00KB
Start:13619200 #2 Memory Usage:180.00KB
Start:13619200 #3 Memory Usage:184.00KB
Start:13619200 #4 Memory Usage:184.00KB
Start:13619200 #5 Memory Usage:188.00KB
*/
?>