I want to store a date and time in an application where compactness is paramount. As well as the datetime, I want to save the associated timezone. While I could just store the timezone bias -i.e. a number in the range -660..840 it would be better to store something that would enable me to identify the timezone by name when the data is retrieved.
So rather than storing -360 (i.e. GMT-0600) I could distinguish between
Central Standard Time and
Central Standard time (Mexico).
I notice that the registry has an enumeration of timezones at
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\ which includes a key called
Index for each entry.
- Is this index that I am after?
- Is it documented somewhere?
- Is the enumeration of this index liable to change in the future?