[SOLVED] What is a callback function and how do I use it with OOP

What is a callback function and how do I use it with OOP

I want to use the php simple HTML DOM parser to grab the image, title, date, and description from each article on a page full of articles. When looking at the API I notice it has a set_callback which Sets a callback function. However im not sure what this does or how I would use it? In one of the examples its used to call a function which strips out some stuff, im wondering if you have to use this to call all functions?

I guess im wondering why I use this, and what does it do as I have never come across a callback function before!

Solution

Here's a basic callback function example:

<?php

function thisFuncTakesACallback($callbackFunc)
{
    echo "I'm going to call $callbackFunc!<br />";
    $callbackFunc();
}

function thisFuncGetsCalled()
{
    echo "I'm a callback function!<br />";
}

thisFuncTakesACallback( 'thisFuncGetsCalled' );
?>

You can call a function that has its name stored in a variable like this: $variable().

So, in the above example, we pass the name of the thisFuncGetsCalled function to thisFuncTakesACallback() which then calls the function passed in.