[patch] gnomecal : erratic results when traversing DST boundaries.

[Mike McEwan <mike lotusland demon co uk>]

  I've been using `gnomecal' as downloaded from CVS earlier today. It
says 1.0.7, despite a posting from Miguel on this list that 1.0.8 had
been released?

  Anyways, whilst using the `month' or `year' views, months/years were 
being missed or "sticking" when using the toolbar's next/prev
buttons. A session with gdb revealed that these problems were occurring 
when, in attempting to calculate the new time for a given view, a
daylight saving time boundary was being crossed. `mktime' was
undesirably adjusting its resultant time value by the appropriate DST
offset. 

  I've appended a patch, which I'm sending to this list as I don't know
where else to. There are probably a couple of other functions where
similar modifications should be made, but I thought I should keep
changes to the minimum that "did it" for me.

  Connected with this, I noticed that when navigating months/years in
this way, the next entity switched to is in respect of the time value
stored in `gcal->current_display'. This means that if you go to say
`2010' in the year view, and then switch to a month view still showing 
the current month in this year, the next month navigated to via the
next/prev toolbar buttons will be relative to that month in
`2010'. How should the various `views' operate? Should they `follow'
each other (e.g. if you got to `2010' in the year view and switch to
any of the other views, they would be displaying there day/week/month
values relative to `2010'), or should each `view' be navigable
independently of the others?

  The patch...

1999-06-07  Mike McEwan  <mike@lotusland.demon.co.uk>

	* timeutil.c (time_add_month): Tell `mktime' that we don't know
 	about daylight saving time so that it does *not* make adjustments
 	when we traverse a DST boundary.
	(time_year_begin): ditto.
	(time_year_end): ditto.
	(time_month_begin): ditto.
	(time_month_end): ditto.


--- gncal/timeutil.c.orig	Thu Mar 11 01:35:52 1999
+++ gncal/timeutil.c	Mon Jun  7 20:30:48 1999
@@ -147,6 +147,7 @@
 	 */
 
 	tm->tm_mon += months;
+	tm->tm_isdst = -1;
 	if ((new_time = mktime (tm)) == -1){
 		g_warning ("mktime could not handling adding a month with\n");
 		print_time_t (time);
@@ -232,6 +233,7 @@
 	tm.tm_sec  = 0;
 	tm.tm_mon  = 0;
 	tm.tm_mday = 1;
+	tm.tm_isdst = -1;
 
 	return mktime (&tm);
 }
@@ -248,6 +250,7 @@
 	tm.tm_mon  = 0;
 	tm.tm_mday = 1;
 	tm.tm_year++;
+	tm.tm_isdst = -1;
 
 	return mktime (&tm);
 }
@@ -262,6 +265,7 @@
 	tm.tm_min  = 0;
 	tm.tm_sec  = 0;
 	tm.tm_mday = 1;
+	tm.tm_isdst = -1;
 
 	return mktime (&tm);
 }
@@ -277,6 +281,7 @@
 	tm.tm_sec  = 0;
 	tm.tm_mday = 1;
 	tm.tm_mon++;
+	tm.tm_isdst = -1;
 
 	return mktime (&tm);
 }


-- 
Mike.