Addslashes twin brother function in PHP

Addslashes is wrong. I want to show you a code to see if you can find the error? Echo function_exists ('addcslashes'); // check whether the function echo get_magic_quotes_gpc () exists (). '<br/>'; // checks whether automatic escape echo php_version is enabled. '<br/>'; // PHP version information echo addcslashes ("Who's John Adams? "); Echo '<br/>'; $ STR =" Who's John Adams? "; Echo addslashes ($ Str); do you think the output results are the same ??? A: The same as B: I think it is the same, but it is actually a pitfall! 105.3.6 warning: addcslashes () expects exactly 2 parameters, 1 given in/data/bookuu/test/class. php on line 50 who \'s John Adams? One error and the other normal output. Why? Addslashes and addcslashes are not the same function. They are not found to have only one character. However, the functions of both functions are the same-escape strings. What is the difference? Addslashes only has one parameter-the string addcslashes requires two parameters. The string, separator. Echo addcslashes ("Who's John Adams? "," '"); In this way, the output can be normally written.