Date: Sun, 16 Sep 2001 07:25:29 GMT From: groggy@iname.com To: "freebsd-questions" <questions@freebsd.org> Subject: file locking #2 Message-ID: <200109160725.HAA34229@groggy.anc.acsalaska.net>
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4.3 FBSD. > i never got an answer to this question i posted a few weeks ago, > nd cuz it's important to some scripting i am doing, > i thought i'd try again. > > FBSD's file locking scheme changed somewhat from version 2 to version 3. in > v2 a user could open the same file on multiple terminals with RW > permissions. in v3, this could'nt be done, only the 1st instance of opening > a file would have RW permission; instances thereafter would have only R > permission. > > however with v3, server processes always have RW permission, even if the > file is currently open with in a user process with RW permission. > > it makes some sense, but i am not sure that i understand this scheme > completely, since file locking now has somewhat of a split personality. > > does it come down to this: user/interactive login shell processes only have > RW on the first instance of a file being opened, while all other processes > have RW permission always? > > also - how do one know when to use file locks in scripts - what quantity of > data is safe to write to a file with other processes possibly simultaneously > writing to the same file? > > thank you. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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