#include <stdio.h>                                         
#include <sys/time.h>   
#include <unistd.h>    

int main()
{
  struct timeval start, end;
  unsigned long spend_time;

  gettimeofday( &start, NULL );
  printf("start : %d.%d\n", start.tv_sec, start.tv_usec);
  sleep(1);
  gettimeofday( &end, NULL );
  printf("end  : %d.%d\n", end.tv_sec, end.tv_usec);

  //微秒时差
  spend_time=1000000*(end.tv_sec-start.tv_sec)+(end.tv_usec-start.tv_usec);
  printf("%ld\n",spend_time);

  return 0;
}