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我需要计算运行某个函数所需的时间并遇到以下代码，记录并输出一段代码的执行时间（以纳秒为单位）

而且两者之间有什么区别吗

struct timeval timer_spent&timeval timer_spent

/* Put this line at the top of the file: */
#include <sys/time.h>

/* Put this right before the code you want to time: */
struct timeval timer_start, timer_end;
gettimeofday(&timer_start, NULL);

/* Put this right after the code you want to time: */
gettimeofday(&timer_end, NULL);
double timer_spent = timer_end.tv_sec - timer_start.tv_sec + (timer_end.tv_usec - timer_start.tv_usec);
printf("Time spent: %.6f\n", timer_spent)/1000000.0;

但我需要以纳秒为单位的精确时间。我对 timeval 结构一无所知。

所以请帮助我的家伙.. !!

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1 回答 1

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但我需要以纳秒为单位的精确时间。

然后使用

int clock_gettime(clockid_t clk_id, struct timespec *tp);

它以秒和纳秒为单位返回时间

struct timespec {
  time_t   tv_sec;        /* seconds */
  long     tv_nsec;       /* nanoseconds */
};

有用的链接：

于 2014-02-03T05:37:56.070 回答