Ctime

time_t  timev;
time(&timev)

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

int main(void){
  time_t t = time(NULL);
  struct tm tm = *localtime(&t);

  printf("now: %d-%d-%d %d:%d:%d\n",
         tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
         tm.tm_hour, tm.tm_min, tm.tm_sec);

  return 0;
}