[tz] NetBSD vs Darwin timezone API (was: tzdata2016g missing version info)

[Christos Zoulas]

On Nov 10,  2:44pm, eggert at cs.ucla.edu (Paul Eggert) wrote:
-- Subject: Re: NetBSD vs Darwin timezone API (was: tzdata2016g missing versi

| Come to think of it, perhaps we should add a options arg to the 
| reference tzalloc too (for compatibility we'd define a new function like 
| tzalloc but with an option arg). One option could be whether the 
| implementation should revisit the installed tz binary file every time 
| localtime_rz or mktime_z is called (for efficiency perhaps it could use 
| file notification on systems where that works well). Another option, 
| while we're on the topic, could be whether to count leap seconds. I'll 
| CC: this to Christos Zoulas (the NetBSD time guru) to see whether he 
| thinks this sort of thing would be a good idea.

I think it is a good idea to have a tzalloc that auto-refreshes the zone
file if it has changed. It should fairly straight-forward to implement. I
propose to make this the default behavior (tzalloc returns a zone that will
auto-update) since most programs would want that and provide a
tzalloc_{frozen,noupdate,stable}() (or whatever we decide to call it) for
those who want the data to stay the same since the open.

If you like this and decide on the name, I can provide a sample implementation.

Best,

christos