#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
|| defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)
#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
|| defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE)
struct tm *gmtime_r (const time_t *, struct tm *);
struct tm *localtime_r (const time_t *, struct tm *);
char *asctime_r (const struct tm *, char *);
struct tm *gmtime_r (const time_t *, struct tm *);
struct tm *localtime_r (const time_t *, struct tm *);
char *asctime_r (const struct tm *, char *);
int clock_nanosleep (clockid_t, int, const struct timespec *, struct timespec *);
int clock_getcpuclockid (pid_t, clockid_t *);
int clock_nanosleep (clockid_t, int, const struct timespec *, struct timespec *);
int clock_getcpuclockid (pid_t, clockid_t *);
struct sigevent;
int timer_create (clockid_t, struct sigevent *, timer_t *);
int timer_delete (timer_t);
struct sigevent;
int timer_create (clockid_t, struct sigevent *, timer_t *);
int timer_delete (timer_t);