Release hung shared memory or semaphores

[fid509]

To view the shares memory and semaphores in Unix you can type the command:

ipcs

This shows you the following:

IPC status from <running system> as of Mon Feb 17 14&#58;24&#58;39 CET 2003
T         ID      KEY        MODE        OWNER    GROUP
Message Queues&#58;
Shared Memory&#58;
m      14021   0x784a7d00 --rw-rw-rw-   smtscd helpdsks
m         82     0             --rw-rw-rw-     root     root
Semaphores&#58;
s    1900563   0x784a7d00 --ra-ra-ra-   smtscd helpdsks
s         80       0             --ra-ra-ra-     root     root

Now you can release the semaphore by typing

ipcrm -s 1900563

or the shared memory with

ipcrm -m 14021

[tommy]

And You can even combine the 2 last commands:

ipcrm -s 1900563 -m 14021

[jherold]

I've needed to use the ipcs command to release semaphores on my system but I haven't been given a reason from support about why it happens.

Does anyone have any idea?

Jim :-?

SC 5.0.1
HP-UX 11

[tommy]

The command IPCS does not release them it only displays them

It is IPCRM that releases them and it is normally only required if sc crashes or processes are killed manually.

[brunodg]

You can kill them with this command:

scenter -shutipc

[dev01]

what version of SC does this happen in and what does semaphores do to SC