linux clock_gettime 的使用方法

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

#define MAKE_NS(S,N) (S*1000000000+N) //将timespec中的时间转换成纳秒计数

void test_time(){
    struct timespec cur_time;
    unsigned long t0,t1;
    clock_gettime(CLOCK_MONOTONIC, &cur_time);
    t0 = MAKE_NS(cur_time.tv_sec,cur_time.tv_nsec);
    usleep(1000*500);
    clock_gettime(CLOCK_MONOTONIC, &cur_time);
    t1 = MAKE_NS(cur_time.tv_sec,cur_time.tv_nsec);
    printf("interval = %ld t0:%ld t1:%ld \n", t1-t0,t0,t1);
}