Chris Lawrence writes:

"""
The GNU folks, in their infinite wisdom, have decided not to implement
altzone in libc6; this would not be horrible, except that timezone
(which is implemented) includes the current DST setting (i.e. timezone
for Central is 18000 in summer and 21600 in winter).  So Python's
timezone and altzone variables aren't set correctly during DST.

Here's a patch relative to 1.5.2b2 that (a) makes timezone and altzone
show the "right" thing on Linux (by using the tm_gmtoff stuff
available in BSD, which is how the GLIBC manual claims things should
be done) and (b) should cope with the southern hemisphere.  In pursuit
of (b), I also took the liberty of renaming the "summer" and "winter"
variables to "july" and "jan".  This patch should also make certain
time calculations on Linux actually work right (like the tz-aware
functions in the rfc822 module).

(It's hard to find DST that's currently being used in the southern
hemisphere; I tested using Africa/Windhoek.)
"""

1 files changed, 28 insertions, 18 deletions

diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index c6d275a..0694ca4 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -616,7 +616,7 @@ inittime()
 	/* Squirrel away the module's dictionary for the y2k check */
 	Py_INCREF(d);
 	moddict = d;
-#ifdef HAVE_TZNAME
+#if defined(HAVE_TZNAME) && !defined(__GNU_LIBRARY__)
 	tzset();
 #ifdef PYOS_OS2
 	ins(d, "timezone", PyInt_FromLong((long)_timezone));
@@ -634,32 +634,42 @@ inittime()
 #endif
 	ins(d, "daylight", PyInt_FromLong((long)daylight));
 	ins(d, "tzname", Py_BuildValue("(zz)", tzname[0], tzname[1]));
-#else /* !HAVE_TZNAME */
+#else /* !HAVE_TZNAME && !__GNU_LIBRARY__ */
 #if HAVE_TM_ZONE
+#error "HAVE_TM_ZONE"
 	{
 #define YEAR ((time_t)((365 * 24 + 6) * 3600))
 		time_t t;
 		struct tm *p;
-		long winterzone, summerzone;
-		char wintername[10], summername[10];
-		/* XXX This won't work on the southern hemisphere.
-		  XXX Anybody got a better idea? */
+		long janzone, julyzone;
+		char janname[10], julyname[10];
 		t = (time((time_t *)0) / YEAR) * YEAR;
 		p = localtime(&t);
-		winterzone = -p->tm_gmtoff;
-		strncpy(wintername, p->tm_zone ? p->tm_zone : "   ", 9);
-		wintername[9] = '\0';
+		janzone = -p->tm_gmtoff;
+		strncpy(janname, p->tm_zone ? p->tm_zone : "   ", 9);
+		janname[9] = '\0';
 		t += YEAR/2;
 		p = localtime(&t);
-		summerzone = -p->tm_gmtoff;
-		strncpy(summername, p->tm_zone ? p->tm_zone : "   ", 9);
-		summername[9] = '\0';
-		ins(d, "timezone", PyInt_FromLong(winterzone));
-		ins(d, "altzone", PyInt_FromLong(summerzone));
-		ins(d, "daylight",
-                    PyInt_FromLong((long)(winterzone != summerzone)));
-		ins(d, "tzname",
-                    Py_BuildValue("(zz)", wintername, summername));
+		julyzone = -p->tm_gmtoff;
+		strncpy(julyname, p->tm_zone ? p->tm_zone : "   ", 9);
+		julyname[9] = '\0';
+		
+		if( janzone < julyzone ) {
+			/* DST is reversed in the southern hemisphere */
+			ins(d, "timezone", PyInt_FromLong(julyzone));
+			ins(d, "altzone", PyInt_FromLong(janzone));
+			ins(d, "daylight",
+			    PyInt_FromLong((long)(janzone != julyzone)));
+			ins(d, "tzname",
+			    Py_BuildValue("(zz)", julyname, janname));
+		} else {
+			ins(d, "timezone", PyInt_FromLong(janzone));
+			ins(d, "altzone", PyInt_FromLong(julyzone));
+			ins(d, "daylight",
+			    PyInt_FromLong((long)(janzone != julyzone)));
+			ins(d, "tzname",
+			    Py_BuildValue("(zz)", janname, julyname));
+		}
 	}
 #else
 #ifdef macintosh