当调用clock_gettime()时，返回的tv_nsec字段实际上可能超过一秒钟吗? [英] When invoking clock_gettime() may the returned tv_nsec field actually exceed a second?

问题描述

当您调用clock_gettime()时，它将返回一个timespec结构.

When you invoke clock_gettime() it returns a timespec structure.

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

我在手册页中没有找到tv_nsec不会超过一秒的保证.保证金实际上存在吗?是否可以依赖于Linux的库(glibc?)实现?

I don't find in the man page a garantee that the tv_nsec won't exceed one second. Does the garantee exist actually ? Could it be dependant on the library (glibc?) implementation for linux?

关键思想是:我是否需要对来自clock_gettime()函数的结果进行归一化"?

The key idea is : do I need to 'normalize' any result coming from the clock_gettime() function?

推荐答案

根据公开组

tv_nsec成员仅在大于或等于零时才有效，并且 小于每秒的纳秒数(十亿).这 此结构描述的时间间隔为(tv_sec * 10'-.4m'9'.4m' + tv_nsec)纳秒.

The tv_nsec member is only valid if greater than or equal to zero, and less than the number of nanoseconds in a second (1000 million). The time interval described by this structure is (tv_sec * 10'-.4m'9'.4m' + tv_nsec) nanoseconds.

因此，根据opengroup，官方认为它必须少于1秒.

So according to opengroup, it looks official that it must be less than 1 second.

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