Description:
------------
I don't know whether this is a bug or a documentation problem.

In SplFileObject::fgets documentation,

Example is shown as following:
<?php
$file = new SplFileObject("file.txt");
while (!$file->eof()) {
    echo $file->fgets();
}
?>

But this should be:
<?php
$file = new SplFileObject("file.txt");
while (($buffer = $file->fgets("file.txt")) !== "") {
    echo $buffer;
}
?>

I show you the test script.

Test script:
---------------
<?php

$arr = array();
$file = new SplFileObject("empty_file.txt");
while (!$file->eof()) {
    $arr[] = $file->fgets();
}
var_dump($arr);

Expected result:
----------------
array(1) {
  [0]=>
  bool(false)
}

# Actually, this substitution should not occurr.

Actual result:
--------------
array(1) {
  [0]=>
  string(0) ""
}

# I think this can give us lots confusion.