#include <stdio.h>
#include <stdlib.h>
#include <time.h>

void
check_year (int year)
{
  struct tm tm;
  tm.tm_year = year - 1900;
  tm.tm_mon = 7;
  tm.tm_mday = 1;
  tm.tm_hour = tm.tm_min = tm.tm_sec = 0;
  tm.tm_isdst = 1;
  time_t t = mktime (&tm);
  if (t != (time_t) -1)
    {
      char buf[1000];
      strftime (buf, sizeof buf, "%Y-%m-%d %H:%M:%S %z %Z", &tm);
      puts (buf);
    }
}

int
main (void)
{
  setenv ("TZ", "Pacific/Apia", 1);
  check_year (2029);
  check_year (2030);
}