Linux下的时间函数：设置及获取时间

一、时间函数

time_t time(time_t *t);

char *asctime(const struct tm *tm);

char *asctime_r(const struct tm *tm, char *buf);

char *ctime(const time_t *timep);

char *ctime_r(const time_t *timep, char *buf);

struct tm *gmtime(const time_t *timep); //获取的为英国时间

struct tm *gmtime_r(const time_t *timep, struct tm *result);

struct tm *localtime(const time_t *timep); //获取的为本地时间,注意与英国时间的区别。

struct tm *localtime_r(const time_t *timep, struct tm *result);

time_t mktime(struct tm *tm);

double difftime(time_t time1, time_t time0);

int gettimeofday(struct timeval *tv, struct timezone *tz);

int settimeofday(const struct timeval *tv , const struct timezone *tz);

二、设置和获取时间

#include <stdio.h>

#include <time.h>

int main(void)

{

time_t t1;

time_t t2;

struct tm *my_tm;

char buf[128] = {0};

//自Epoch (00:00:00 UTC, January 1,1970)的秒数

t1 = time(&t1);

printf("%d\n", t1); //1355905754

t2 = time(&t2);

sleep(1);

printf("%lf\n", difftime(t2, t1)); //t1,t2相差:1.000000，有时候可以用这个函数来做伪定时器

printf("%s\n",ctime(&t1)); //Wed Dec 19 16:29:14 2012

//init tm

my_tm->tm_year = 2012-1900;

my_tm->tm_mon = 12-1;

my_tm->tm_mday = 12;

my_tm->tm_hour = 12;

my_tm->tm_min = 12;

my_tm->tm_sec = 12;

//设置时间

t1 = mktime(my_tm);

//获取时间

my_tm = localtime(&t1);

sprintf(buf, "%04d-%02d-%02d %02d:%02d:%02d",

my_tm->tm_year + 1900, my_tm->tm_mon + 1, my_tm->tm_mday, my_tm->tm_hour, my_tm->tm_min, my_tm->tm_sec);

printf("%s\n", buf); //2012-12-12 12:12:12

return 0;

}