timestamp conversion problem.

Applications Programming
1

Hi all.

I have the following code:

#include<stdio.h>
#include<time.h>
int main()
{
      struct tm tm;
      time_t time = 1262322000; /*Jan, 01, 2010*/
      char temp[128];
      int i = 0;
      while(i < 4)
      {
            memset(temp, 0, 128);
            localtime_r(&time, &tm);
            strftime(temp, 16, "%G%m%d", &tm);
            printf("%s\n", temp);
            ++i;
            time += 86400;
       }
}

The output is:
20090101
20090102
20090103
20100104
Instead of:
20100101
20100102
20100103
20100104
here are the tm values after calling localtime_r for each iteration:

(gdb) p tm
$1 = {tm_sec = 0, tm_min = 0, tm_hour = 0, tm_mday = 1, tm_mon = 0, tm_year = 110, tm_wday = 5, tm_yday = 0, tm_isdst = 0, tm_gmtoff = -18000, 
  tm_zone = 0x1201080 "EST"}
$2 = {tm_sec = 0, tm_min = 0, tm_hour = 0, tm_mday = 2, tm_mon = 0, tm_year = 110, tm_wday = 6, tm_yday = 1, tm_isdst = 0, tm_gmtoff = -18000, 
  tm_zone = 0x1201080 "EST"}
$3 = {tm_sec = 0, tm_min = 0, tm_hour = 0, tm_mday = 3, tm_mon = 0, tm_year = 110, tm_wday = 0, tm_yday = 2, tm_isdst = 0, tm_gmtoff = -18000, 
  tm_zone = 0x1201080 "EST"}
$4 = {tm_sec = 0, tm_min = 0, tm_hour = 0, tm_mday = 4, tm_mon = 0, tm_year = 110, tm_wday = 1, tm_yday = 3, tm_isdst = 0, tm_gmtoff = -18000, 
  tm_zone = 0x1201080 "EST"}

tm_year is always 110.

Can anyone explain what's going on here?
Why the year for first three iterations is 2009?
Thanks!

2

Compare these two descriptions from the man page of strftime:

Notice the (subtle) difference? %G will format the year as the one that has the Monday of the Week, which in your case is the last week of 2009 (2009-12-28 to be exact). Change your %G to %Y, and you'll be fine.

3

Thanks a lot!! It fixed the problem!