Messages in this thread | | | Date | Tue, 23 Mar 2010 05:32:11 +1030 | From | David Newall <> | Subject | Re: SysV IPC message queues |
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Kyle,
Processes do not open nor close message queues, rather they place messages on and fetch them from queues. Let me say this again: you do not open a queue like you must for a file, but go directly to the equivalent of read and write. There is no refcount to indicate how many processes are "using" a queue, although there may be one indicating how many are actively waiting to receive a message. Removing a queue when that count reaches zero would be quite wrong because a process stops waiting as soon as it receives a message; so the count would be zero more often than not.
Do not allow IPC_PRIVATE to lead you into false understanding of what a message queue is. IPC_PRIVATE does not cause creation of a private queue, as indicated in msgget(2): "The name choice IPC_PRIVATE was perhaps unfortunate, IPC_NEW would more clearly show its function." Queues are not accessed by key but by id. You do not need to know the key for a queue to access it, neither do you need to use msgget(2) to find a queue's id.
So, no, sorry, but your idea must be rejected.
David
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