http://aspn.activestate.com/ASPN/Products/PHP/ref.shmop.html

Example 1. Shared Memory Operations Overview

<?php

// Create 100 byte shared memory block with system id if 0xff3
$shm_id = shmop_open(0xff3, "c", 0644, 100);
if(!$shm_id) {
	echo "Couldn't create shared memory segment\n";
}

// Get shared memory block's size
$shm_size = shmop_size($shm_id);
echo "SHM Block Size: ".$shm_size. " has been created.\n";

// Lets write a test string into shared memory
$shm_bytes_written = shmop_write($shm_id, "my shared memory block", 0);
if($shm_bytes_written != strlen("my shared memory block")) {
	echo "Couldn't write the entire length of data\n";
}

// Now lets read the string back
$my_string = shmop_read($shm_id, 0, $shm_size);
if(!$my_string) {
	echo "Couldn't read from shared memory block\n";
}
echo "The data inside shared memory was: ".$my_string."\n";

//Now lets delete the block and close the shared memory segment
if(!shmop_delete($shm_id)) {
	echo "Couldn't mark shared memory block for deletion.";
}
shmop_close($shm_id);

?>