note 49183 added to function.function-exists

Why this function doesn't return true while checking the function empty()? e.g. <?php $sFunctionname = "empty"; if (function_exists("$sFunctionname")) { echo "Function $sFunctionname() was found!"; } else { echo "Function $sFunctionname() couldn't be found!"; } ?> returns "Function empty() couldn't be found!" I've discussed this with a co-worker and he mentioned, that function_exists() maybe watches in a "function list" for functions, that were not part of the php distribution from the beginning. But I've tested this with the mail() function, which is part of PHP since version 3, and it returned true! Isn't the empty() function a function? ---- Manual Page -- http://www.php.net/manual/en/function.function-exists.php Edit -- http://master.php.net/manage/user-notes.php?action=edit+49183 Delete: added to the manual -- http://master.php.net/manage/user-notes.php?action=delete+49183&report=yes&reason=added+to+the+manual Delete: bad code -- http://master.php.net/manage/user-notes.php?action=delete+49183&report=yes&reason=bad+code Delete: spam -- http://master.php.net/manage/user-notes.php?action=delete+49183&report=yes&reason=spam Delete: useless -- http://master.php.net/manage/user-notes.php?action=delete+49183&report=yes&reason=useless Delete: other reasons -- http://master.php.net/manage/user-notes.php?action=delete+49183&report=yes Reject -- http://master.php.net/manage/user-notes.php?action=reject+49183&report=yes Search -- http://master.php.net/manage/user-notes.php