Wait for php callback on object instance and return value on function

Question

I have the following function that instantiates an object and runs its method. I want to return $to_return but the problem is that $to_return does not change even when the function is using 'use' keyword. Here is the function:

function some_function($arg){

    $to_return = false;

    $object = new Object;

    $to_return = $object->METHOD(function($callback) use ($to_return){

        $to_return = $some_var;

    });

    $to_return = $object->runMETHOD("some_arg");

    return $to_return;

}

So, basically:

• $to_return returned is always false
• I want some_function to return $some_var

In short: how can I make some_function return the object changed inside the object method?

Answer 1

All you miss is indicating that $to_return should be passed by reference:

function($callback) use (& $to_return)

Also example of working example on 3v4l: https://3v4l.org/Vfp70

I'm no internals expert, but long story short primitives are "copied" when you pass them somewhere thus what you were setting in the callback is not transfered outside. Objects, on the other hand, would behave like you expected because pointer to object is passed and original instance is modifed. Using even plain stdClass as such transporter would work, as illustrated in this 3v4l: https://3v4l.org/m9jJ3