Set the TZ env to get the UTC-ms since epoch.

runtime/vm/os_win.cc

Index: runtime/vm/os_win.cc
diff --git a/runtime/vm/os_win.cc b/runtime/vm/os_win.cc
index 2acef13fe304b92e735082d851fb144e2524bd51..076eb4c083c3eb45f91ffbcb72c933bd415aa95f 100644
--- a/runtime/vm/os_win.cc
+++ b/runtime/vm/os_win.cc
@@ -7,6 +7,7 @@
 #include <time.h>
 
 #include "platform/assert.h"
+#include "vm/thread.h"

[Ivan Posva, 2012/04/11 12:01:24]

ditto

[floitsch, 2012/04/11 12:10:21]

Done.

 
 namespace dart {
 
@@ -18,9 +19,6 @@ bool OS::BreakDownSecondsSinceEpoch(time_t seconds_since_epoch,
   if (in_utc) {
     error_code = gmtime_s(&tm_result, &seconds_since_epoch);
   } else {
-    // TODO(floitsch): we should be able to call tzset only once during
-    // initialization.
-    tzset();  // Make sure the libc knows about the local zone.
     error_code = localtime_s(&tm_result, &seconds_since_epoch);
   }
   result->year = tm_result.tm_year;
@@ -46,25 +44,19 @@ bool OS::BrokenDownToSecondsSinceEpoch(
   // Set wday to an impossible day, so that we can catch bad input.
   tm_broken_down.tm_wday = -1;
   // Make sure the libc knows about the local zone.
-  // In case of 'in_utc' this call is mainly for multi-threading issues. If
-  // another thread uses a time-function it will set the timezone. The timezone
-  // adjustement below would then not work anymore.
   // TODO(floitsch): we should be able to call tzset only once during
   // initialization.
   tzset();
   if (in_utc) {
     // Disable daylight saving in utc mode.
     tm_broken_down.tm_isdst = 0;
-    // mktime assumes that the given date is local time zone.
-    *result = mktime(&tm_broken_down);
-    // Remove the timezone.
-    *result -= timezone;
+    *result = _mkgmtime(&tm_broken_down);
   } else {
     // Let libc figure out if daylight saving is active.
     tm_broken_down.tm_isdst = -1;
     *result = mktime(&tm_broken_down);
   }
-  if ((*result == -1) && (tm_broken_down.tm_wday == -1)) {
+  if ((*result == -1 || *result == 1) && (tm_broken_down.tm_wday == -1)) {
     return false;
   }
   return true;