Syntax of addslashes
string addslashes(string string)
Returns escaped characters in string that have special meaning in SQL database queries. Single quotes (”), double quotes (“”), backslashes (), and the NUL-byte (\0) are escaped. The stripslashes() function is the inverse for this function
Example of addslashes
<?php
$str = "O'Reilly?";
eval("echo '" . addslashes($str) . "';");
?>