(PHP 5, PHP 7, PHP 8)
php_strip_whitespace — Return source with stripped comments and whitespace
$filename): string
   Returns the PHP source code in filename with
   PHP comments and whitespace removed. This may be useful for determining the
   amount of actual code in your scripts compared with the amount of comments.
   This is similar to using php -w from the
   commandline.
  
filenamePath to the PHP file.
The stripped source code will be returned on success, or an empty string on failure.
Note:
This function respects the value of the short_open_tag ini directive.
Example #1 php_strip_whitespace() example
<?php
// PHP comment here
/*
 * Another PHP comment
 */
echo        php_strip_whitespace(__FILE__);
// Newlines are considered whitespace, and are removed too:
do_nothing();
?>
The above example will output:
<?php echo php_strip_whitespace(__FILE__); do_nothing(); ?>
Notice the PHP comments are gone, as are the whitespace and newline after the first echo statement.