c - 关闭文件时 feof() 的返回值是多少？

Question

对于 FILE* 流，如果我读取尽可能多的数据，feof(stream) 返回非零值。然后，如果我关闭流，它 feof(stream) 会继续返回一个非零值吗？有保证吗？

Answer 1

在一个关闭的文件上调用 feof() 是没有意义的(实际上比没有意义更糟糕——它是未定义的所以任何事情都有可能发生)。

来自 C 标准:

The value of a pointer to a FILE object is indeterminate after the associated file is closed (including the standard text streams).

和

A successful call to the fclose function causes the stream pointed to by stream to be flushed and the associated file to be closed. Any unwritten buffered data for the stream are delivered to the host environment to be written to the file; any unread buffered data are discarded. Whether or not the call succeeds, the stream is disassociated from the file and any buffer set by the setbuf or setvbuf function is disassociated from the stream (and deallocated if it was automatically allocated).