Appendix E. PHP reserved words

Here is the list of PHP reserved words, usually constants and predefined variables. You won't find any functions here, but rather language constructs. You shouldn't try to use such names as variable, function, constant or method names, as it will surely lead to confusion.

and	E_PARSE	old_function
$argv	E_ERROR	or
as	E_WARNING	parent
$argc	eval	PHP_OS
break	exit()	$PHP_SELF
case	extends	PHP_VERSION
cfunction	FALSE	print()
class	for	require()
continue	foreach	require_once()
declare	function	return
default	$HTTP_COOKIE_VARS	static
do	$HTTP_GET_VARS	switch
die()	$HTTP_POST_VARS	stdClass
echo()	$HTTP_POST_FILES	$this
else	$HTTP_ENV_VARS	TRUE
elseif	$HTTP_SERVER_VARS	var
empty()	if	xor
enddeclare	include()	virtual()
endfor	include_once()	while
endforeach	global	__FILE__
endif	list()	__LINE__
endswitch	new	__sleep
endwhile	not	__wakeup
E_ALL	NULL