portable gmtime_r testing

xp_gmtime_r.c

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

#if defined(__MINGW64_VERSION_MAJOR)
/* XXX why isn't this in sec_api/time_s.h? */
# if defined(_USE_32BIT_TIME_T)
#  define gmtime_s _gmtime32_s
# else
#  define gmtime_s _gmtime64_s
# endif
#elif defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
# define BUILDING_WITH_MINGW32
# define gmtime_r(tp, tm) (gmtime((tp)))
# define localtime_r(tp, tm) (localtime((tp)))
#endif

#if defined(_MSC_VER) || defined(__MINGW64_VERSION_MAJOR)
# define gmtime_r(tp, tm) ((gmtime_s((tm), (tp)) == 0) ? (tm) : NULL)
# define localtime_r(tp, tm) ((localtime_s((tm), (tp)) == 0) ? (tm) : NULL)
#endif


int
main(int argc, char *argv[])
{
  time_t rawtime;
  struct tm utc_tm, local_tm, tmp_tm, *my_utc_tm, *my_local_tm;
  char buffer[1024] = "";

  time(&rawtime);
  my_utc_tm = gmtime_r(&rawtime, &utc_tm);

#ifdef BUILDING_WITH_MINGW32
  /* save the *utc_tm so it doesn't get clobbered */
  memcpy(&tmp_tm, my_utc_tm, sizeof(struct tm));
  my_utc_tm = &tmp_tm;
#endif

  my_local_tm = localtime_r(&rawtime, &local_tm);


  if (strftime(buffer, sizeof(buffer),
               "UTC: %A, %B %d, %Y %H:%M", my_utc_tm))
    puts(buffer);

  if (strftime(buffer, sizeof(buffer),
               "Local: %A, %B %d, %Y %H:%M %z", my_local_tm))
    puts(buffer);

  return 0;
}

/* vim: set ts=2 sts=2 sw=2 et: */

Windows 7 mingw-w64 (4.6.3, 4.7.1), mingw (4.6.2), msvc cl (16.00.30319.01)

UTC: Tuesday, May 15, 2012 12:57
Local: Tuesday, May 15, 2012 08:57 Eastern Daylight Time

Arch Linux 3.3.6 (gcc 4.7.0), Ubuntu 12.04 (gcc 4.6.3)

UTC: Tuesday, May 15, 2012 13:01
Local: Tuesday, May 15, 2012 09:01 -0400