Pass a function by reference in PHP

Question

Is it possible to pass functions by reference?

Something like this:

function call($func){
    $func();
}

function test(){
    echo \"hello world!\";         


        

Answer 1

No, functions are not first class values in PHP, they cannot be passed by their name literal (which is what you're asking for). Even anonymous functions or functions created via create_function are passed by an object or string reference.

You can pass a name of a function as string, the name of an object method as (object, string) array or an anonymous function as object. None of these pass pointers or references, they just pass on the name of the function. All of these methods are known as the callback pseudo-type: http://php.net/callback