note 16651 deleted from function.shmop-open by cmb
| From: | cmb@php.net | Date: | Wed, 13 May 2020 09:14:51 +0000 |
| Subject: | note 16651 deleted from function.shmop-open by cmb | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-214620@lists.php.net to get a copy of this message | ||
Note Submitter: Mitchell_Shnier at ieee dot orgZ
----
To check whether a particular shared memory segment is already created, you need to concatenate the
"a" and "c" flags. For example (where $SystemKey is the Unix key used by the
other process(es) with which you want to share this memory segment)...<BR>
$shm_id = shmop_open($SystemKey, "ac", 0, 0);
if ($shm_id) {
#it is already created
} else {
#you need to create it with shmop_open using "c" only
}<BR>
Using only "a" does not work (just as using only IPC_EXCL in the Unix shmget() call is
meaningless). Also, use the ipcs shell command to see your shared memory segments.