gettimeofday() -- 获取当前时间(保存在结构体timeval中)

#include <stdio.h>

#include <sys/time.h>

#include <time.h>

int main(int argc, char * argv[]){

struct timeval tv; //(1)

while(1){

gettimeofday(&tv, NULL); //(2)

printf("time %u:%u\n", tv.tv_sec, tv.tv_usec);

sleep(2);

}

return 0;

}

(1)
struct--timeval

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

struct timeval {

time_t tv_sec; /* seconds */

suseconds_t tv_usec; /* microseconds */

};

millisecond 毫秒

microsecond 微秒

timeval表示一个时间点，比如:

timeval.tv_sec = 1 (s)

timevat.tv_usec = 500 000 (μs)

1:500 = 1s500000μs = 1.5s

(2) gettimeofday()

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

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

The functions gettimeofday() and settimeofday() can get and set the time as well as a timezone.

The use of the timezone structure is obsolete; the tz argument should normally be specified as NULL.

(3) 运行结果:

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

time 1181788367:991487

time 1181788369:991602

表示睡眠2秒经过的精确时间为： 2s115μs