获取毫秒或微秒- Linux (C/C++)中的精确启动时间

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

int main() {
    struct timespec start_time;
    clock_gettime(CLOCK_MONOTONIC, &start_time);
    
    // 执行需要计时的代码
    
    struct timespec end_time;
    clock_gettime(CLOCK_MONOTONIC, &end_time);
    
    long long elapsed_time = (end_time.tv_sec - start_time.tv_sec) * 1000000000LL + (end_time.tv_nsec - start_time.tv_nsec);
    double elapsed_ms = elapsed_time / 1000000.0;
    
    printf("Elapsed time: %.3f ms\n", elapsed_ms);
    
    return 0;
}

#include <stdio.h>
#include <sys/time.h>

int main() {
    struct timeval start_time;
    gettimeofday(&start_time, NULL);
    
    // 执行需要计时的代码
    
    struct timeval end_time;
    gettimeofday(&end_time, NULL);
    
    long long elapsed_time = (end_time.tv_sec - start_time.tv_sec) * 1000000LL + (end_time.tv_usec - start_time.tv_usec);
    double elapsed_ms = elapsed_time / 1000.0;
    
    printf("Elapsed time: %.3f ms\n", elapsed_ms);
    
    return 0;
}