| ID | Used with | Description |
|---|---|---|
FILTER_FLAG_STRIP_LOW |
FILTER_SANITIZE_ENCODED,
FILTER_SANITIZE_SPECIAL_CHARS,
FILTER_SANITIZE_STRING,
FILTER_UNSAFE_RAW
|
Strips characters that have a numerical value <32. |
FILTER_FLAG_STRIP_HIGH |
FILTER_SANITIZE_ENCODED,
FILTER_SANITIZE_SPECIAL_CHARS,
FILTER_SANITIZE_STRING,
FILTER_UNSAFE_RAW
|
Strips characters that have a numerical value >127. |
FILTER_FLAG_ALLOW_FRACTION |
FILTER_SANITIZE_NUMBER_FLOAT
|
Allows a period (.) as a fractional separator in numbers. |
FILTER_FLAG_ALLOW_THOUSAND |
FILTER_SANITIZE_NUMBER_FLOAT,
FILTER_VALIDATE_FLOAT
|
Allows a comma (,) as a thousands separator in numbers. |
FILTER_FLAG_ALLOW_SCIENTIFIC |
FILTER_SANITIZE_NUMBER_FLOAT
|
Allows an e or E for scientific notation in numbers. |
FILTER_FLAG_NO_ENCODE_QUOTES |
FILTER_SANITIZE_STRING
|
If this flag is present, single (') and double (") quotes will not be encoded. |
FILTER_FLAG_ENCODE_LOW |
FILTER_SANITIZE_ENCODED,
FILTER_SANITIZE_STRING,
FILTER_SANITIZE_RAW
|
Encodes all characters with a numerical value <32. |
FILTER_FLAG_ENCODE_HIGH |
FILTER_SANITIZE_ENCODED,
FILTER_SANITIZE_SPECIAL_CHARS,
FILTER_SANITIZE_STRING,
FILTER_SANITIZE_RAW
|
Encodes all characters with a numerical value >127. |
FILTER_FLAG_ENCODE_AMP |
FILTER_SANITIZE_STRING,
FILTER_SANITIZE_RAW
|
Encodes ampersands (&). |
FILTER_NULL_ON_FAILURE |
FILTER_VALIDATE_BOOLEAN
|
Returns NULL for unrecognized boolean values.
|
FILTER_FLAG_ALLOW_OCTAL |
FILTER_VALIDATE_INT
|
Regards inputs starting with a zero (0) as octal numbers. This only allows the succeeding digits to be 0-7. |
FILTER_FLAG_ALLOW_HEX |
FILTER_VALIDATE_INT
|
Regards inputs starting with 0x or 0X as hexadecimal numbers. This only allows succeeding characters to be a-fA-F0-9. |
FILTER_FLAG_IPV4 |
FILTER_VALIDATE_IP
|
Allows the IP address to be in IPv4 format. |
FILTER_FLAG_IPV6 |
FILTER_VALIDATE_IP
|
Allows the IP address to be in IPv6 format. |
FILTER_FLAG_NO_PRIV_RANGE |
FILTER_VALIDATE_IP
|
Fails validation for the following private IPv4 ranges: 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. Fails validation for the IPv6 addresses starting with FD or FC. |
FILTER_FLAG_NO_RES_RANGE |
FILTER_VALIDATE_IP
|
Fails validation for the following reserved IPv4 ranges: 0.0.0.0/8, 169.254.0.0/16, 192.0.2.0/24 and 224.0.0.0/4. This flag does not apply to IPv6 addresses. |
FILTER_FLAG_PATH_REQUIRED |
FILTER_VALIDATE_URL
|
Requires the URL to contain a path part. |
FILTER_FLAG_QUERY_REQUIRED |
FILTER_VALIDATE_URL
|
Requires the URL to contain a query string. |
FILTER_REQUIRE_SCALAR |
Requires the value to be scalar. | |
FILTER_REQUIRE_ARRAY |
Requires the value to be an array. | |
FILTER_FORCE_ARRAY |
If the value is a scalar, it is treated as array with the scalar value as only element. |