Today I noticed my Plan 9 machine displayed time which is 1 hr past
surrounding world. Digging around, I found that DST start/end dates
for Eastern-European Time (/adm/timezone/EET) for current year are
bad. Those follow pre-1996 conventions for ending dates and does DST
switch 2 hours later. For more information, see
http://en.wikipedia.org/wiki/European_Summer_Time.
Bundled program prints valid pair of dates for a given year in
1996-2099 range.
Yaroslav.
# To unbundle, run this file
echo eet.c
sed 's/.//' >eet.c <<'//GO.SYSIN DD eet.c'
-/* Calculates DST start/end dates for EET timezone on a year given on
-cmdline. {8c eet.c && 8l eet.8 && 8.out} */
-#include <u.h>
-#include <libc.h>
-
-void
-main(int argc, char* argv[])
-{
- int yr = 2009;
- Tm tm[] = {{
- .sec = 0,
- .min = 0,
- .hour = 1,
- .mday = 0,
- .mon = 2,
- .year = 0,
- .wday = 0,
- .zone = "GMT",
- .tzoff = 0
- }, {
- .sec = 0,
- .min = 0,
- .hour = 1,
- .mday = 0,
- .mon = 9,
- .year = 0,
- .wday = 0,
- .zone = "GMT",
- .tzoff = 0
- }};
-
- if(argc > 1)
- yr = atoi(argv[1]);
-
- tm[0].year = tm[1].year = (yr - 1900);
- tm[0].mday = (31 - (5*yr/4 + 4) % 7);
- tm[1].mday = (31 - (5*yr/4 + 1) % 7);
- /* formulas are valid until 2099 */
-
- print("%d %d\n", tm2sec(&tm[0]), tm2sec(&tm[1]));
- exits(nil);
-}
//GO.SYSIN DD eet.c
