c语言 tm时间结构体

C语言中tm结构体 

struct tm
{
  int tm_sec;                   /* Seconds.     [0-60] (1 leap second) */
  int tm_min;                   /* Minutes.     [0-59] */
  int tm_hour;                  /* Hours.       [0-23] */
  int tm_mday;                  /* Day.         [1-31] */
  int tm_mon;                   /* Month.       [0-11] */
  int tm_year;                  /* Year - 1900.  */
  int tm_wday;                  /* Day of week. [0-6] */
  int tm_yday;                  /* Days in year.[0-365] */
  int tm_isdst;                 /* DST.         [-1/0/1]*/

#ifdef  __USE_BSD
  long int tm_gmtoff;           /* Seconds east of UTC.  */
  __const char *tm_zone;        /* Timezone abbreviation.  */
#else
  long int __tm_gmtoff;         /* Seconds east of UTC.  */
  __const char *__tm_zone;      /* Timezone abbreviation.  */
#endif
};

在C语言中
有time_t tm timeval等几种类型的时间
1.time_t为typedef __int64 __time64_t;
2.struct timeval
{
      uint tv_sec;
      uint tv.usec;
}



具体操作函数
包含文件:

tm *gmtime(time_t * t);
time_t time(time_t *t);
char *asctime(const struct tm *timeptr);
char *ctime(const time_t *timer); 
把tm指针转换为time_t
time_t mktime(struct tm *timeptr);
localtime和gmtime的区别在于gmtime将时间转换为国际标准格式，也就是相对于1970 00:00:00开始的时间戳
而localtime是相对于本地的时区的格式。
#include
#include
#include
#include
#include
void quit_t()
{
        printf("eixt now");
        exit(-1);
}
int main()
{
/*      struct timeval  vt;
        gettimeofday(&vt , NULL);
        while(1)
        {
                printf("%u:%u\n",vt.tv_sec,vt.tv_usec);
                sleep(2);
                signal(SIGINT, quit_t);
        }
*/

        struct tm *tt;
        time_t t = time(NULL);
        tt = gmtime(&t);
        //char *s = asctime(tt);
        printf("%d-%d-%d %d:%d:%d",tt->tm_year+1900,tt->tm_mon+1,tt->tm_mday,tt->tm_hour,tt->tm_min,tt->tm_sec);
        return 0;
}