Proposal - drop the GPSD JSON driver

Hal Murray hmurray at
Thu Oct 20 05:36:29 UTC 2016

esr at 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.

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.

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.

These are my opinions.  I hate spam.

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