How to unset a function definition just like we unset a variable?

Question

I want to define a function and unset it after its use just like we do with variables.

$a = 'something'; unset($a); echo $a; // outputs nothing 

Just like this if i declare a function callMethod(), is there a way to unset it?

Answer 1

As of PHP 5.3, you can assign an anonymous function to a variable, then unset it:

$upper = function($str) {     return strtoupper($str); };  echo $upper('test1'); // outputs: TEST1  unset($upper);  echo $upper('test2'); // Notice: Undefined variable: upper // Fatal error: Function name must be a string 

Before 5.3, you can do something similar with create_function()

$func = create_function('$arg', 'return strtoupper($arg);'); echo $func('test1'); unset($func);  $func2 = "\0lambda_1"; echo $func2('test2.a'), "\n"; // Same results, this is the "unset" $func function  echo $func('test2.b'); // Fatal Error 

Answer 2

runkit_function_remove — Remove a function definition http://php.net/manual/en/function.runkit-function-remove.php