04.08: find a portable way to obtain the timezone offset
Portable GMT offset calculation to display correct
time on GSM.
Change-Id: I673f17af2550c9708c4771e4ea4eafbbfafbb824
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index d97bde2..58c5610 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -496,12 +496,19 @@
else {
/* Need to get GSM offset and convert into 15 min units */
/* This probably breaks if gmtoff returns a value not evenly divisible by 15? */
- local_time = localtime(&cur_t);
#ifdef HAVE_TM_GMTOFF_IN_TM
+ local_time = localtime(&cur_t);
tzunits = (local_time->tm_gmtoff/60)/15;
#else
-#warning find a portable way to obtain the timezone offset
- tzunits = 0;
+ /* find timezone offset */
+ time_t utc;
+ double offsetFromUTC;
+ utc = mktime(gmt_time);
+ local_time = localtime(&cur_t);
+ offsetFromUTC = difftime(cur_t, utc);
+ if (local_time->tm_isdst)
+ offsetFromUTC += 3600.0;
+ tzunits = ((int)offsetFromUTC) / 60 / 15;
#endif
if (tzunits < 0) {
tzunits = tzunits/-1;