相关疑难解决方法(0)

我正在尝试使用time()来衡量我的程序的各个点.

我不明白为什么之前和之后的值是一样的？我知道这不是描述我的程序的最佳方式,我只想看看有多长时间.

printf("**MyProgram::before time= %ld\n", time(NULL));

doSomthing();
doSomthingLong();

printf("**MyProgram::after time= %ld\n", time(NULL));

我试过了:

struct timeval diff, startTV, endTV;

gettimeofday(&startTV, NULL); 

doSomething();
doSomethingLong();

gettimeofday(&endTV, NULL); 

timersub(&endTV, &startTV, &diff);

printf("**time taken = %ld %ld\n", diff.tv_sec, diff.tv_usec);

我如何阅读结果**time taken = 0 26339？这是否意味着26,339纳秒= 26.3毫秒？

那怎么说**time taken = 4 45025,这意味着4秒和25毫秒？