Re: Upcoming: handy history extensions

["Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxx>]

On May 5, 10:11am, Peter Stephenson wrote:
} Subject: Re: Upcoming: handy history extensions
}
} > Another issue is history-file locking.  I think we want to lock the
} > file when doing incremental updating (especially since re-writing
} > now occurs much more frequently).
} 
} [...] checking for fcntl/F_SETLKW etc., lockf/F_LOCK etc., flock/LOCK_SH
} etc. should be straightforward [...]

It would be much better to go with a file-based locking protocol, like the
one in procmail.  I believe there's a freely-reusable module in procmail
to create those locks; there's a copy of same in the mush mailer sources
(ftp://cse.ogi.edu/pub/mush) if the one in procmail is too ugly.

} Then there's the whole Lockdaemon From Hell saga, which we had
} better just forget about.

If you don't want your shell locking up your entire machine, you'd better
not forget about it ... which is why using any of the kernel-based locking
mechanisms is right out.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com