Re: MAIL_USE_FLOCK and Debian.

[Richard Stallman]

    OK.  After thinking about it a bit more, I agree.  You're absolutely
    right that a run-time setting would be better.  However, part of the
    problem is that this policy is currently handled by the external
    movemail program, so we'd have to figue out how to allow runtime
    customization.  I would guess perhaps an /etc file, or command-line
    arguments, though the latter probably wouldn't make it easy enough to
    provide site-wide defaults...

A command line argument would let Emacs control the decision, but I
think that is undesirable.  People might use movemail from other
programs too.  We don't want to make it easy to use movemail wrong.
So movemail itself should figure out which way to do the job.

I think that the existence of some file somewhere in the file system
is the right way to control this.

    I think so, but with regard to the implementation.  I think one of the
    complicating factors is that the actual policies can be reasonably
    complex, i.e. do you use flock and something else, flock first or
    last, etc?

I thought we had just three alternatives to consider: liblockfile, and
the two alternatives now implemented in movemail.   Now you seem to be
proposing additional alternatives.  I am not sure exactly what they are;
it sounds like you propose that movemail do more than one of those three.
Why do you propose that?

      - I'm not sure if you know, but for Debian at least, the locking
        strategy embodied in liblockfile is also a well-defined algorithm,
        and policy doesn't actually require programs to use liblockfile
        (as far as I recall), but just requires them to follow the
        algorithm specified, so it would be possible to DTRT straight from
        emacs.

This does not affect the issue as far as I can see.