TIMEVAL
struct timeval { long tv_sec; /* seconds */ long tv_usec; /* and microseconds */};
select ÇÔ¼ö¿¡¼ ŸÀӾƿô °ªÀ¸·Î »ç¿ëµÇ´Â ±¸Á¶Ã¼·Î, BSD ÆÄÀÏÀÎ sys/time.h ·ÎºÎÅÍ °¡Á®¿Ô½À´Ï´Ù.