Re: lockfiles and mutual exclusion
>>>>> "Adrian" == Adrian Bridgett <email@example.com> writes:
Adrian> update-menus forks to the background and waits for dpkg to
Adrian> finish before continuing to work. This is a useful
Adrian> function that could be useful for other programs (for
Adrian> instance scripts that build automated indexes of other
Adrian> Is there a cunning way to achieve this at present?
Grab `procmail', and RTFM `lockfile'. That's one way it can be done.
There's a little program with `smartlist' too, called `led' or
something, that's a wrapper around an editorling. It makes a
lockfile, then starts the ed on the procmail run-control file you are
working on. As long as the lockfile is present, `procmail' will hang
out until you're done.
I wrote some XEmacs lisp code for editting procmail rc files that
does a similar thing. Some of you may like to have it; it's in my
http dirs at:
... it's called `led-funcs.el' or suchlike. It's a first pass effort
and could use a workover, but functions well enough to use now.
A lock like this is called a "mutex lock". (do I pass the quiz? or
am I misusing the terms?) That means "mutual exclusion lock". As
long as the programs involved honor the locking scheme, they'll not
stomp on one another.
`dpkg' and `dselect' make a lock file; I know because I've tried to
start it while it's already running on another tty, and it told
 Not necessarily a sensible editor.
 There's a few other things in there you might like to have. :-)
mailto:firstname.lastname@example.org (Karl M. Hegbloom)
Portland, OR USA
Debian GNU 1.3.1+hamm Linux 2.0.32 AMD K5 PR-133
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