On the linux kernel, COW filesystems like BTRFS, BcacheFS, etc Inode numbers are not usable to determine if something is the same file.
This is intentional.
(PHP 4, PHP 5, PHP 7, PHP 8)
fileinode — Gets file inode
filenamePath to the file.
Returns the inode number of the file, or false on failure.
Upon failure, an E_WARNING is emitted.
Example #1 Comparing the inode of a file with the current file
<?php
$filename = 'index.php';
if (getmyinode() == fileinode($filename)) {
echo 'You are checking the current file.';
}
?>Note: The results of this function are cached. See clearstatcache() for more details.
As of PHP 5.0.0, this function can also be used with some URL wrappers. Refer to Supported Protocols and Wrappers to determine which wrappers support stat() family of functionality.
On the linux kernel, COW filesystems like BTRFS, BcacheFS, etc Inode numbers are not usable to determine if something is the same file.
This is intentional.As documented in https://www.php.net/manual/en/function.stat.php#refsect1-function.stat-returnvalues:
> On Windows, as of PHP 7.4.0, this is the identifier associated with the file, which is a 64-bit unsigned integer, so may overflow. Previously, it was always 0.
It appears that fileinode shares the same underlying implementation.