(PECL xdiff >= 0.2.0)
xdiff_file_merge3 — Merge 3 files into one
xdiff_file_merge3 ( string $old_file , string $new_file1 , string $new_file2 , string $dest ) : mixed
 Merges three files into one and stores the result in a file dest. The old_file is an original version while new_file1 and new_file2 are modified versions of an original. 
old_file
Path to the first file. It acts as "old" file.
new_file1
 Path to the second file. It acts as modified version of old_file. 
new_file2
 Path to the third file. It acts as modified version of old_file. 
dest
 Path of the resulting file, containing merged changed from both new_file1 and new_file2. 
 Returns true if merge was successful, string with rejected chunks if it was not or false if an internal error happened. 
Example #1 xdiff_file_merge3() example
The following code merges three files into one.
<?php
$old_version = 'original_script.php';
$fix1 = 'script_with_fix1.php';
$fix2 = 'script_with_fix2.php';
$errors = xdiff_file_merge3($old_version, $fix1, $fix2, 'fixed_script.php');
if (is_string($errors)) {
    echo "Rejects:\n";
    echo $errors;
}
?> 
    © 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
    https://www.php.net/manual/en/function.xdiff-file-merge3.php