Proposal - drop the GPSD JSON driver
Eric S. Raymond
esr at thyrsus.com
Thu Oct 20 10:57:07 UTC 2016
Hal Murray <hmurray at megapathdsl.net>:
> esr at thyrsus.com said:
> >> So, we all vote for JSON in POSIX SHM?
> > I don't. I think this is one of the very rare cases where passing a C stru=
> > ct as a binary blob makes sense. We want to minimize offset and jitter and
> > there's no cross-architecture problem.
> Don't forget to include a version number. Or maybe 2.
First field, or fields.
> There is still a nasty problem of how to change the contents of that struct.
> In general, you can't assume that you can update both ends at the same time.
I expect changes to be rare. But yes.
> If you normally add fields, I think you can swap in new code on the source
> side as long as the version info is handled properly. I think you need 2
> version numbers. One is the current version. The other is the oldest
> version that will work.
That's a good plan.
<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>
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