The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
FILTER_FLAG_STRIP_LOW
(int)
Strip characters with ASCII value less than 32.
FILTER_FLAG_STRIP_HIGH
(int)
Strip characters with ASCII value greater than 127.
FILTER_FLAG_STRIP_BACKTICK
(int)
Strips backtick (`) characters.
FILTER_FLAG_ENCODE_LOW
(int)
Encode characters with ASCII value less than 32.
FILTER_FLAG_ENCODE_HIGH
(int)
Encode characters with ASCII value greater than 127.
FILTER_FLAG_ENCODE_AMP
(int)
Encode &.
FILTER_FLAG_NO_ENCODE_QUOTES
(int)
Single and double quotes (' and ")
will not be encoded.
FILTER_FLAG_EMPTY_STRING_NULL
(int)
If sanitizing a string results in an empty string,
convert the value to null