fusl/src/time/timegm.c

#define _GNU_SOURCE
#include "time_impl.h"
#include <errno.h>

extern const char __gmt[];

time_t timegm(struct tm* tm) {
  struct tm new;
  long long t = __tm_to_secs(tm);
  if (__secs_to_tm(t, &new) < 0) {
    errno = EOVERFLOW;
    return -1;
  }
  *tm = new;
  tm->tm_isdst = 0;
  tm->__tm_gmtoff = 0;
  tm->__tm_zone = __gmt;
  return t;
}