[tz] tz abbreviations / zdump for programmers

Zefram zefram at fysh.org
Wed Jun 6 16:00:16 UTC 2012

Ian Abbott wrote:
>I also noticed that Windows 7 displays the same zone name to the user
>as "(UTC) Dublin, Edinburgh, Lisbon, London"

So they've moved on from "GMT" to "UTC".  The parenthesised part
previously referred, and presumably still refers, to the zone's "standard"
(non-DST) offset from UT.  So for London it's "GMT" and for Paris it's
"GMT+1", for example, regardless of whether DST is in effect.

It seems extremely unlikely that they're making any meaningful distinction
between GMT and UTC (i.e., the sub-second difference between flavours
of UT).  Of course, hardly anyone else makes that distinction in a
timezone context anyway.

>                                            Perhaps the use of "UTC"
>to mean "legal time in Eire, Scotland, Portugal and England" is even
>more confusing than "GMT"!

Are they doing that?  The existing misuse of "GMT" is in the strings
"GMT Standard Time" and "GMT Daylight Time", which name the two states
of the timezone.  Have those changed to "UTC Standard Time" and "UTC
Daylight Time"?  The "(GMT) ... London", as I noted above, is describing
one of the offsets, and neither that nor "(UTC) ... London" is incorrect
for that purpose.  Albeit a bit misleading: its purpose would be clearer
if it had an explicit "+0".


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