Managing Interprocess Communication (IPC)

Users can invoke applications that create IPC resources and wait for IPC resources. IPC resources are not automatically released when a process is ended or a user logs off. Therefore, it is possible that an IPC user might need assistance to do either of the following:

Remove an IPC resource using the shell's ipcrm command
Remove an IPC resource using the shell's ipcrm command to release a user from an IPC wait state

Example: To display IPC resources and which user ID owns the resource:

ipcs -w

Tip: To delete message queue IDs, use the ipcrm -q or ipcrm -Q command.

Another problem might occur when a user waits a long time for a resource such as semaphores or a message receive. Removing a message queue ID or semaphore ID brings any user in an IPC wait state out of the wait state.

Example: To display which users are waiting for semaphores and message queues:

ipcs -w