Linux系统下精确到微秒级的时间操作函数

#include <sys/time.h>#include <stdio.h>#include <math.h>void function()/*用来耗用一定的时间而已，无实际用处的函数*/{  unsigned int i,j;  double y;  for(i=0;i<10000;i++)    for(j=0;j<10000;j++)      y=sin((double)i);}int main(int argc, char ** argv){  struct timeval tpstart,tpend;  float timeuse;  gettimeofday(&tpstart,NULL);  function();  gettimeofday(&tpend,NULL);  timeuse=1000000*(tpend.tv_sec-tpstart.tv_sec)+tpend.tv_usec-tpstart.tv_usec;  timeuse/=1000000;  PRintf("Used Time:%f/n",timeuse);  exit(0);}

struct timeval {               long tv_sec;        /* seconds */               long tv_usec;  /* microseconds */       };