MonetDB: Jun2016 - Changes to the way we find out the current ti...

[Sjoerd Mullender]

Changeset: 761203f6742a for MonetDB
URL: http://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=761203f6742a
Modified Files:
        NT/monetdb_config.h.in
        clients/mapiclient/mclient.c
        configure.ag
Branch: Jun2016
Log Message:

Changes to the way we find out the current time zone.
On Windows, there is a function GetDynamicTimeZoneInformation which
returns whether we're in standard of daylight saving time, and also
provides information about the offset to UTC.
On Linux (and presumably other glibc environments), there is a field
tm_gmtoff in the tm struct that gives the current offset to UTC.


diffs (84 lines):

diff --git a/NT/monetdb_config.h.in b/NT/monetdb_config.h.in
--- a/NT/monetdb_config.h.in
+++ b/NT/monetdb_config.h.in
@@ -187,6 +187,11 @@
 /* Define to 1 if you have the `getaddrinfo' function. */
 #define HAVE_GETADDRINFO 1
 
+/* Define to 1 if you have the `GetDynamicTimeZoneInformation' function. */
+#ifdef _MSC_VER
+#define HAVE_GETDYNAMICTIMEZONEINFORMATION 1
+#endif
+
 /* Define to 1 if you have the `getexecname' function. */
 /* #undef HAVE_GETEXECNAME */
 
@@ -211,11 +216,6 @@
 /* Define to 1 if you have the `gettimeofday' function. */
 /* #undef HAVE_GETTIMEOFDAY */
 
-/* Define to 1 if you have the `_get_timezone' function. */
-#ifdef _MSC_VER
-#define HAVE__GET_TIMEZONE 1
-#endif
-
 /* Define if you have the gsl library */
 /* #undef HAVE_GSL */
 
diff --git a/clients/mapiclient/mclient.c b/clients/mapiclient/mclient.c
--- a/clients/mapiclient/mclient.c
+++ b/clients/mapiclient/mclient.c
@@ -2849,15 +2849,33 @@ set_timezone(Mapi mid)
        MapiHdl hdl;
 
        /* figure out our current timezone */
-#ifdef HAVE__GET_TIMEZONE
-       __time64_t ltime, lt, gt;
-       struct tm loctime;
+#if defined HAVE_GETDYNAMICTIMEZONEINFORMATION
+       DYNAMIC_TIME_ZONE_INFORMATION tzinf;
 
-       _time64(&ltime);
-       _localtime64_s(&loctime, &ltime);
-       lt = _mktime64(&loctime);
-       gt = _mkgmtime64(&loctime);
-       tzone = (int) (lt - gt);
+       /* documentation says: UTC = localtime + Bias (in minutes),
+        * but experimentation during DST period says, UTC = localtime
+        * + Bias + DaylightBias, and presumably during non DST
+        * period, UTC = localtime + Bias */
+       switch (GetDynamicTimeZoneInformation(&tzinf)) {
+       case TIME_ZONE_ID_STANDARD:
+       case TIME_ZONE_ID_UNKNOWN:
+               tzone = (int) tzinf.Bias * 60;
+               break;
+       case TIME_ZONE_ID_DAYLIGHT:
+               tzone = (int) (tzinf.Bias + tzinf.DaylightBias) * 60;
+               break;
+       default:
+               /* call failed, we don't know the time zone */
+               tzone = 0;
+               break;
+       }
+#elif defined HAVE_STRUCT_TM_TM_ZONE
+       time_t t;
+       struct tm *tmp;
+
+       t = time(NULL);
+       tmp = localtime(&t);
+       tzone = (int) -tmp->tm_gmtoff;
 #else
        time_t t, lt, gt;
        struct tm *tmp;
diff --git a/configure.ag b/configure.ag
--- a/configure.ag
+++ b/configure.ag
@@ -3213,6 +3213,8 @@ if test $mn_cv_have__sys_siglist = yes; 
        AC_DEFINE(HAVE__SYS_SIGLIST, 1, [Define if you have _sys_siglist])
 fi
 
+AC_STRUCT_TIMEZONE
+
 dnl check dependencies (might need more than just SQL)
 if test x"$enable_sql" = xyes && test x"$enable_monetdb5" = x"no" ; then
        AC_MSG_ERROR([MonetDB/SQL requires MonetDB5${disable_monetdb5:+ 
$disable_monetdb5}.])
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