file.eof() returns false, even if file is at EOF.

[stianeikeland]

I open a file containing two bytes. Check EOF - false. Read two bytes, check EOF - false, read one byte - EOF error.

Is there a problem with File.eof() here, or am I doing something wrong?

use std::io::File;

// Create testfile using:
// echo -n -e '\x66\x6f' > testfile

fn main() {
    let mut fh = File::open(&Path::new("testfile")).unwrap();

    println!("{}", fh.eof()); // false
    println!("{}", fh.read_le_u16().unwrap()); // 28518
    println!("{}", fh.eof()); // false
    println!("{}", fh.read_u8().unwrap());
    // task '<main>' failed at 'called `Result::unwrap()`
    // on an `Err` value: couldn't read file (end of file; path=testfile)'
}

[sfackler]

The current behavior is consistent with C's feof. There isn't really any good way for the stream to know that it's at the end of the file unless the OS returns an EOF indicator after a read, which won't happen until you try to read beyond the end of it.

[alexcrichton]

I'm going to flag this as a docs bug because this behavior should be documented in the method.

[stianeikeland]

Aha, that explains it, thanks! Yeah, would be great with a notice in the docs.

[steveklabnik]

I mis-spelled 'fixes' so bors didn't close this.