&reftitle.constants; &extension.constants; INPUT_POST (integer) POST variables. INPUT_GET (integer) GET variables. INPUT_COOKIE (integer) COOKIE variables. INPUT_ENV (integer) ENV variables. INPUT_SERVER (integer) SERVER variables. INPUT_SESSION (integer) SESSION variables. (not implemented yet) INPUT_REQUEST (integer) REQUEST variables. (not implemented yet) FILTER_FLAG_NONE (integer) No flags. FILTER_REQUIRE_SCALAR (integer) Flag used to require scalar as input FILTER_REQUIRE_ARRAY (integer) Require an array as input. FILTER_FORCE_ARRAY (integer) Always returns an array. FILTER_NULL_ON_FAILURE (integer) Use NULL instead of FALSE on failure. FILTER_VALIDATE_INT (integer) ID of "int" filter. FILTER_VALIDATE_BOOLEAN (integer) ID of "boolean" filter. FILTER_VALIDATE_FLOAT (integer) ID of "float" filter. FILTER_VALIDATE_REGEXP (integer) ID of "validate_regexp" filter. FILTER_VALIDATE_URL (integer) ID of "validate_url" filter. FILTER_VALIDATE_EMAIL (integer) ID of "validate_email" filter. FILTER_VALIDATE_IP (integer) ID of "validate_ip" filter. FILTER_VALIDATE_MAC (integer) ID of "validate_mac_address" filter. (Available as of PHP 5.5.0) FILTER_DEFAULT (integer) ID of default ("unsafe_raw") filter. This is equivalent to FILTER_UNSAFE_RAW. FILTER_UNSAFE_RAW (integer) ID of "unsafe_raw" filter. FILTER_SANITIZE_STRING (integer) ID of "string" filter. FILTER_SANITIZE_STRIPPED (integer) ID of "stripped" filter. FILTER_SANITIZE_ENCODED (integer) ID of "encoded" filter. FILTER_SANITIZE_SPECIAL_CHARS (integer) ID of "special_chars" filter. FILTER_SANITIZE_EMAIL (integer) ID of "email" filter. FILTER_SANITIZE_URL (integer) ID of "url" filter. FILTER_SANITIZE_NUMBER_INT (integer) ID of "number_int" filter. FILTER_SANITIZE_NUMBER_FLOAT (integer) ID of "number_float" filter. FILTER_SANITIZE_MAGIC_QUOTES (integer) ID of "magic_quotes" filter. FILTER_CALLBACK (integer) ID of "callback" filter. FILTER_FLAG_ALLOW_OCTAL (integer) Allow octal notation (0[0-7]+) in "int" filter. FILTER_FLAG_ALLOW_HEX (integer) Allow hex notation (0x[0-9a-fA-F]+) in "int" filter. FILTER_FLAG_STRIP_LOW (integer) Strip characters with ASCII value less than 32. FILTER_FLAG_STRIP_HIGH (integer) Strip characters with ASCII value greater than 127. FILTER_FLAG_ENCODE_LOW (integer) Encode characters with ASCII value less than 32. FILTER_FLAG_ENCODE_HIGH (integer) Encode characters with ASCII value greater than 127. FILTER_FLAG_ENCODE_AMP (integer) Encode &. FILTER_FLAG_NO_ENCODE_QUOTES (integer) Don't encode ' and ". FILTER_FLAG_EMPTY_STRING_NULL (integer) (No use for now.) FILTER_FLAG_ALLOW_FRACTION (integer) Allow fractional part in "number_float" filter. FILTER_FLAG_ALLOW_THOUSAND (integer) Allow thousand separator (,) in "number_float" filter. FILTER_FLAG_ALLOW_SCIENTIFIC (integer) Allow scientific notation (e, E) in "number_float" filter. FILTER_FLAG_PATH_REQUIRED (integer) Require path in "validate_url" filter. FILTER_FLAG_QUERY_REQUIRED (integer) Require query in "validate_url" filter. FILTER_FLAG_IPV4 (integer) Allow only IPv4 address in "validate_ip" filter. FILTER_FLAG_IPV6 (integer) Allow only IPv6 address in "validate_ip" filter. FILTER_FLAG_NO_RES_RANGE (integer) Deny reserved addresses in "validate_ip" filter. FILTER_FLAG_NO_PRIV_RANGE (integer) Deny private addresses in "validate_ip" filter. FILTER_FLAG_EMAIL_UNICODE (integer) Accepts Unicode characters in the local part in "validate_email" filter. (Available as of PHP 7.1.0)