c - 二进制流上带有 WHENCE 的 SEEK_END

Question

这个问题已经有答案了:

Understanding undefined behavior for a binary stream using fseek(file, 0, SEEK_END) with a file (1 个回答)

已关闭 4 年前。

我对 C Programming: A Modern Approach, 2nd Edition 的这个说法感到困惑第 446 页，

For binary streams, fseek isn't required to support calls in which whence is SEEK_END

这是为什么呢？这似乎是一个奇怪的规定。

Answer 1

查找in the spec ，它说

Setting the file position indicator to end-of-file, as with fseek(file, 0, SEEK_END), has undefined behavior for a binary stream (because of possible trailing null characters) or for any stream with state-dependent encoding that does not assuredly end in the initial shift state.

所以我猜是空字符的存在导致了这种行为，尽管我不确定为什么它们在这里受到不同的对待。