使用C的庫函數獲取當前本地時間

1. tm結構體

struct tm {

int
tm_sec; /* seconds after the minute [0-60] */
int tm_min;
/* minutes after the hour [0-59] */
int tm_hour;
/* hours since midnight [0-23] */
int tm_mday;
/* day of the month [1-31] */
int tm_mon;
/* months since January [0-11] */
int tm_year;
/* years since 1900 */
int tm_wday;
/* days since Sunday [0-6] */
int tm_yday;
/* days since January 1 [0-365] */
int tm_isdst;
/* Daylight Savings Time flag */
long tm_gmtoff;
/* offset from CUT in seconds */
char *tm_zone;
/* timezone abbreviation */
};

2. 使用localtime獲取本地時間，具體代碼如下

//獲取當前時間，采用C的庫函數，返回值不需要外部釋放，效率方面比使用OC的NSDate類高效3-4倍
- (struct tm*)getTime
{
    //時間格式
    struct timeval ticks;
    gettimeofday(&ticks, nil);
    time_t now;
    struct tm* timeNow;
    time(&now);
    timeNow = localtime(&now);
    timeNow->tm_gmtoff = ticks.tv_usec/1000;  //毫秒
   
    timeNow->tm_year += 1900;    //tm中的tm_year是從1900至今數
    timeNow->tm_mon  += 1;       //tm_mon范圍是0-11
  
    return timeNow;
}