SIPP 代码学习笔记2- 关于时间

SIPP关于时间的代码。

char* CStat::formatTime (struct timeval* P_tv, bool microseconds)
{
static char L_time [TIME_LENGTH];
struct tm * L_currentDate;

// Get the current date and time
L_currentDate = localtime ((const time_t *)&P_tv->tv_sec);

// Format the time
if (L_currentDate == NULL)
{
memset (L_time, 0, TIME_LENGTH);
}
else
{
if (microseconds) {
sprintf(L_time, "%4.4d-%2.2d-%2.2d %2.2d:%2.2d:%2.2d:%03.03f",
L_currentDate->tm_year + 1900,
L_currentDate->tm_mon + 1,
L_currentDate->tm_mday,
L_currentDate->tm_hour,
L_currentDate->tm_min,
L_currentDate->tm_sec,
(double)P_tv->tv_usec/(double)1000.0);
} else {
sprintf(L_time, "%4.4d-%2.2d-%2.2d/t%2.2d:%2.2d:%2.2d:%3.3d/t%10.10d.%6.6d",
L_currentDate->tm_year + 1900,
L_currentDate->tm_mon + 1,
L_currentDate->tm_mday,
L_currentDate->tm_hour,
L_currentDate->tm_min,
L_currentDate->tm_sec,
(int) (P_tv->tv_usec)/1000,
(long) (P_tv->tv_sec),
(long) (P_tv->tv_usec));
}
}
return (L_time);
} /* end of formatTime */

转：C语言中的时间函数localtime和gmtime

作者：linux0818

localtime和gmtime这两个函数采用了time.h中的一个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
};

这两个函数的原型为：

struct tm *localtime(const time_t *timep);

struct tm *gmtime(const time_t *timep);

具体实现为：

localtime.c

---------------------------------------------------------

#include <stdio.h>
#include <time.h>
void cur_time(void);

int main(int argc,char **argv)
{
cur_time();

return 0;
}

void cur_time(void)
{
char *wday[]={"星期天","星期一","星期二","星期三","星期四","星期五","星期六"};
time_t timep;
struct tm *p;
time(&timep);
p=localtime(&timep); /* 获取当前时间 */
printf("%d年%02d月%02d日",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %02d:%02d:%02d/n",wday[p->tm_wday],p->tm_hour,p->tm_min,p->tm_sec);
}

---------------------------------------------------------

gcc localtime.c 后运行a.out结果为：

2007年12月26日星期三 11:07:15

gmtime.c

---------------------------------------------------------

#include <stdio.h>
#include <time.h>
void cur_time(void);

int main(int argc,char **argv)
{
cur_time();
return 0;
}

void cur_time(void)
{
char *wday[]={"星期天","星期一","星期二","星期三","星期四","星期五","星期六"};
time_t timep;
struct tm *p;
time(&timep);
p=gmtime(&timep); /* 获取当前时间 */
printf("%d年%02d月%02d日",(1900+p->tm_year),(1+p->tm_mon),p->tm_mday);
printf("%s %02d:%02d:%02d/n",wday[p->tm_wday],(p->tm_hour+8),p->tm_min,p->tm_sec);
}
-----------------------------------------------------------

gcc gmtime.c 后运行a.out结果为：

2007年12月26日星期三 11:08:34