time.c

来自「足球机器人自动程序」· C语言 代码 · 共 63 行

#include <stdio.h>
#include <time.h>
#include <unistd.h>

inline double nano(long x) {
	return ((double)x) / 1.0e9;
}

int main() {

	struct timespec r1, r2, r3;
	int t1;
	double t2;
	r3.tv_sec = 1;
	r3.tv_nsec = 0;

	if (clock_getres(CLOCK_REALTIME, &r1) < 0) {
		perror("getres");
		return -1;
	}
	printf("%f\n", nano(r1.tv_nsec));

	for (;;) {
		clock_gettime(CLOCK_REALTIME, &r1);
		nanosleep(&r3, NULL);
		clock_gettime(CLOCK_REALTIME, &r2);
		t2 = nano(r2.tv_nsec - r1.tv_nsec);
		t1 = r2.tv_sec - r1.tv_sec;
		if (t2 < 0) {
			t2 += 1.0;
			t1 -= 1;
		}
		printf("%f\t", t2);

		clock_gettime(CLOCK_REALTIME, &r1);
		sleep(1);
		clock_gettime(CLOCK_REALTIME, &r2);
		t2 = nano(r2.tv_nsec - r1.tv_nsec);
		t1 = r2.tv_sec - r1.tv_sec;
		if (t2 < 0) {
			t2 += 1.0;
			t1 -= 1;
		}
		printf("%f\t", t2);

		clock_gettime(CLOCK_REALTIME, &r1);
		usleep(1e6);
		clock_gettime(CLOCK_REALTIME, &r2);
		t2 = nano(r2.tv_nsec - r1.tv_nsec);
		t1 = r2.tv_sec - r1.tv_sec;
		if (t2 < 0) {
			t2 += 1.0;
			t1 -= 1;
		}
		printf("%f\t", t2);

		printf("\n");
	}

	return 0;
}