ctype_cntrl() is a PHP filter function checks if all chars in the $input_string are control characters or not. Any thing other than this if present then it return FALSE.
Control characters are non-printing chars that does not represents a written symbol. Example : \n ( line feed ) , \e escape, \v vertical tab etc..
$var="\n\e\t\v";
if(ctype_cntrl($var)){
echo " All are control characters ";
}else{
echo "All or some are not control characters ";
}
