I made a work around for shmop_read() and shmop_write() to handle strings correctly. shmop_write() doesn't terminate written data with a null byte, and shmop_read() reads the whole memory segment. This is ok if your dealing with binary data so perhaps these functions shouldn't be considered bugged. Perhaps 2 similar functions should be introduced specially for handling strings (that's what most php programmers work with).

Here's the work around with 2 new custom functions for making a string null terminated and extracting a null terminated string from memory:

<?php
error_reporting(E_ALL | E_STRICT);

$key   = make_key('TEST');
$mode  = 'c';
$perms = 0644;
$size  = 80;


$shm_id = shmop_open($key, $mode, $perms, $size);
if (!$shm_id) {
  throw new Exception(sprintf('shmop_open(%x, "%s", 0%o, %u) failed.', $key, $mode, $perms, $size));
}
print 'Opened shm size: ' . shmop_size($shm_id) . "\n";


// Write long string.
$value = str_to_nts('This is a kind of very long string.');
$result = shmop_write($shm_id, $value, 0);
printf("shmop_write(%x, '%s', 0) returned: %d\n", $shm_id, $value, $result);


// Read string back in.
$result = str_from_mem(shmop_read($shm_id, 0, shmop_size($shm_id)));
printf("shmop_read(%x, 0, %d) returned: '%s'\n", $shm_id, shmop_size($shm_id), $result);


// Write short string.
$value = str_to_nts('This is short.');
$result = shmop_write($shm_id, $value, 0);
printf("shmop_write(%x, '%s', 0) returned: %d\n", $shm_id, $value, $result);


// Read string back in.
$result = str_from_mem(shmop_read($shm_id, 0, shmop_size($shm_id)));
printf("shmop_read(%x, 0, %d) returned: '%s'\n", $shm_id, shmop_size($shm_id), $result);


function make_key($value) {
  return ord(substr($value,0,1)) | (ord(substr($value,1,1))<<8) | (ord(substr($value,2,1))<<16) | (ord(substr($value,3,1)) << 24); //intel endian
}


function str_to_nts($value) {
  return "$value\0";
}


function str_from_mem(&$value) {
  $i = strpos($value, "\0");

  print "\n$i\n";

  if ($i === false) {
    return $value;
  }
  $result =  substr($value, 0, $i);
  return $result;
}


?>

Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to report
a bug at http://bugs.php.net/how-to-report.php

Use third parameter of shmop_read().
This is expected behaviour, 'cause one want to can store binary data in shared memory.