Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!eru!luth!sunic!maxim!prc From: prc@erbe.se (Robert Claeson) Newsgroups: comp.unix.wizards Subject: Re: How do I know my Q-KEY is unique ? Keywords: msg queue, queue, message queue, ID Message-ID: <833@maxim.erbe.se> Date: 24 Sep 89 17:05:14 GMT References: <1747@draken.nada.kth.se> Reply-To: prc@erbe.se (Robert Claeson) Organization: ERBE DATA AB, Sweden Lines: 19 In article <1747@draken.nada.kth.se> d88-jwa@nada.kth.se (Jon W{tte) writes: >I am currently considering using message queues for a game I'm writing. >The problem is: when I create a message queue, I pass a (hopefully) >unique 32-bit key. How do I make SURE this key is unique ? (I need to >compile the key into a server as well as a client...) I asked about the same question about 1/2 year ago. The summary of the respones were, that queues (and semaphores and shared memories) should be created with the IPC_PRIVATE key. This forces a new queue to be created. The queue id that I then get can be passed on the command-line to subprocesses that are created (I originally needed this for a terminal driver that I'm still writing). Some people mentioned a "ftokey()" function. I didn't investigate it. From the descriptions that I got, it didn't seem that ftokey is guaranteed to return a unique key. -- Robert Claeson E-mail: rclaeson@erbe.se ERBE DATA AB