检查IPC消息队列是否已经存在而不创建

Question

How can I just check if a message queue exists or not without making it?

When using msgget with O_CREAT | O_EXCL O_CREAT | O_EXCL flag, if it exists, the call will fail with return value -1, but if it doesn't, it will then create a new message queue. Is there any way to just check?

Answer 1

ipcs(1) provides information on the IPC facilities and ipcrm(1) can be used to remove the IPC objects from the system.

List shared memory segments:

ipcs -m

List message queues:

ipcs -q

Remove shared memory segment created with shmkey:

ipcrm -M key

Remove shared memory segment identified by shmid:

ipcrm -m id

Remove message queue created with msgkey:

ipcrm -Q key

Remove message queue identified by msgid:

ipcrm -q id