Is this just a stylistic difference, or does using require_once(\'filename.php\') vs require_once \'filename.php\' have actual load/efficiency diff
require_once(\'filename.php\')
require_once \'filename.php\'
Pear Coding Standards say :
"include_once and require_once are statements, not functions. Parentheses should not surround the subject filename."
Source : http://pear.php.net/manual/en/standards.including.php