Re: [gpsd-dev] Fw: [gpsd-commit-watch] [SCM] GPSD branch, master, updated. release-3.11-483-gd3521ce

[Eric S. Raymond]

Gary E. Miller <address@hidden>:
> Yo Eric!
> 
> commit d3521ce59ba8065ca6e65f95787fcb7d6b0ac60d
> 
>     Simplify NTP SHM segment creation.
>     
> + * We use dummy[0] as an in-use flag, so segments can be released and
> + * reallocated from holes in the sequence.
> 
> Is this a good idea?  Not exactly like we are in control of the 
> canonical use for that byte.

I look at it this way.  The dummy field is a trailing pad that's never
been used.  We know the structure is about to be redesigned; probably
there will still be a dummy member, in which case we win.  If there
isn't, compilation will break noisily - but that was likely to 
happen anyway.
 
> And given the file permissions will likely change soon too, maybe 
> best to negotitate this with the ntpd guys?

I'm sure we're going to have to rework the ntpshm.c code anyway if they do
anything nontrivial (I made my requests to Harlan last night).  So this
is actually a low-risk time to experiment.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>