1. tm结构体

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获取本地时间，具体代码如下

//获取当前时间，采用C的库函数，返回值不需要外部释放，效率方面比使用OC的NSDate类高效3-4倍
- (struct tm*)getTime
{
//时间格式
struct timeva l 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是从1900至今数
timeNow->tm_mon += 1; //tm_mon范围是0-11

return timeNow;
}