Messages in this thread | | | From | "Tom Leete" <> | Subject | Re: How can Emacs get a unique ID per Linux reboot? | Date | Tue, 1 Jun 1999 23:03:27 -0400 |
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-----Original Message----- From: Paul Eggert <eggert@twinsun.com>
>I'm trying to help RMS fix a problem with Linux and recent test >releases of GNU Emacs. When the user edits a file FOO, Emacs 20.3.10 >creates a symbolic link from .#FOO to USER@HOSTNAME:PID:BOOTID, where >BOOTID is a unique identifier for this reboot of the kernel. This >symlink lets Emacs determine whether someone else is editing this >file. The symlink is stale if BOOTID does not correspond to last time >that the kernel was rebooted. (Emacs doesn't rely on lockf or its >relatives to create advisory locks on files; I believe that this is >because they aren't portable and reliable enough with networked file >systems.)
I don't understand why this method works; two users may well be logged onto the same machine & kernel. What does BOOTID give you that HOSTNAME doesn't? Won't a reboot while editing leave a file with a stale lock?
As to lockf, your BOOTID seems to have portability problems too.
Tom Leete
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