Estas constantes están definidas por esta extensión y estarán disponibles sólo cuando la extensión haya sido compilada con PHP, o bien sea cargada dinámicamente en ejecución.
INPUT_POST
    (integer)
   INPUT_GET
    (integer)
   INPUT_ENV
    (integer)
   INPUT_SERVER
    (integer)
   INPUT_SESSION
    (integer)
   INPUT_REQUEST
    (integer)
   FILTER_FLAG_NONE
    (integer)
   FILTER_REQUIRE_SCALAR
    (integer)
   FILTER_REQUIRE_ARRAY
    (integer)
   FILTER_FORCE_ARRAY
    (integer)
   FILTER_NULL_ON_FAILURE
    (integer)
   FILTER_VALIDATE_INT
    (integer)
   FILTER_VALIDATE_BOOLEAN
    (integer)
   FILTER_VALIDATE_FLOAT
    (integer)
   FILTER_VALIDATE_REGEXP
    (integer)
   FILTER_VALIDATE_URL
    (integer)
   FILTER_VALIDATE_EMAIL
    (integer)
   FILTER_VALIDATE_IP
    (integer)
   FILTER_VALIDATE_MAC
    (integer)
   FILTER_DEFAULT
    (integer)
   FILTER_UNSAFE_RAW.
    
   FILTER_UNSAFE_RAW
    (integer)
   FILTER_SANITIZE_STRING
    (integer)
   FILTER_SANITIZE_STRIPPED
    (integer)
   FILTER_SANITIZE_ENCODED
    (integer)
   FILTER_SANITIZE_SPECIAL_CHARS
    (integer)
   FILTER_SANITIZE_EMAIL
    (integer)
   FILTER_SANITIZE_URL
    (integer)
   FILTER_SANITIZE_NUMBER_INT
    (integer)
   FILTER_SANITIZE_NUMBER_FLOAT
    (integer)
   FILTER_SANITIZE_MAGIC_QUOTES
    (integer)
   FILTER_CALLBACK
    (integer)
   FILTER_FLAG_ALLOW_OCTAL
    (integer)
   FILTER_FLAG_ALLOW_HEX
    (integer)
   FILTER_FLAG_STRIP_LOW
    (integer)
   FILTER_FLAG_STRIP_HIGH
    (integer)
   FILTER_FLAG_ENCODE_LOW
    (integer)
   FILTER_FLAG_ENCODE_HIGH
    (integer)
   FILTER_FLAG_ENCODE_AMP
    (integer)
   FILTER_FLAG_NO_ENCODE_QUOTES
    (integer)
   FILTER_FLAG_EMPTY_STRING_NULL
    (integer)
   FILTER_FLAG_ALLOW_FRACTION
    (integer)
   FILTER_FLAG_ALLOW_THOUSAND
    (integer)
   FILTER_FLAG_ALLOW_SCIENTIFIC
    (integer)
   FILTER_FLAG_PATH_REQUIRED
    (integer)
   FILTER_FLAG_QUERY_REQUIRED
    (integer)
   FILTER_FLAG_IPV4
    (integer)
   FILTER_FLAG_IPV6
    (integer)
   FILTER_FLAG_NO_RES_RANGE
    (integer)
   FILTER_FLAG_NO_PRIV_RANGE
    (integer)