Thank you for this bug report. To properly diagnose the problem, we
need a short but complete example script to be able to reproduce
this bug ourselves. 

A proper reproducing script starts with <?php and ends with ?>,
is max. 10-20 lines long and does not require any external 
resources such as databases, etc.

If possible, make the script source available online and provide
an URL to it here. Try avoid embedding huge scripts into the report.

sh.php
<?php $shm_key= 111; $str="I was here."; $shm_id= shmop_open($shm_key, "c", 0644, strlen($str));
 if ($shm_id== false) echo "I was unable to create shmop!<BR>";
 else { $wrb=shmop_write($shm_id,$str, 0); 
        if($wrb!= strlen($str)) echo $wrb." bytes was written of ".strlen($str)."!<BR>";
        echo "shm_id=".$shm_id."<BR>";  shmop_close($shm_id);} ?>

hh.php
<?php $shm_key= 111; $shm_id=@shmop_open($shm_key, "a", 0, 0);
 if ($shm_id== false) echo "Couln'd open shm <".$shm_key.">!<BR>";
 else {$A=shmop_read($shm_id, 0, shmop_size($shm_id)); echo $A."<BR>";
       echo "shm_id=".$shm_id; shmop_close($shm_id); } ?>

hs.php
<?php $shm_key= 111; $shm_id=@shmop_open($shm_key, "a", 0, 0);
 if ($shm_id== false) echo "Couln'd open shm <".$shm_key.">!<BR>";
 else {$A=shmop_read($shm_id, 0, shmop_size($shm_id)); echo $A."<BR>";
        echo "shm_id=".$shm_id;  shmop_delete($shm_id);  shmop_close($shm_id); } ?>

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

SHM is emulated on win32 and the nature of the emulation 
that it would work only in a persistent environment such as 
Apache or IIS (not cgi or cli). 

http://us2.php.net/manual/en/ref.shmop.php says:
<<Note that versions of Windows previous to Windows 2000 do not support shared memory.>>
I use Windows 2000. It's not <previous> and I've not found anything about emulation nor current enviroment.
Sorry, that I don't know Windows enough to undestand that shmop CANN'T work on it properly.
May be, there should be a note in manual?

This bug has been fixed in the documentation's XML sources. Since the
online and downloadable versions of the documentation need some time
to get updated, we would like to ask you to be a bit patient.

Thank you for the report, and for helping us make our documentation better.

As Ilia said, Shmop won't work when PHP is in CLI or CGI mode.