callback functions

[The Little Guy]

I can not thing of a reason why someone would use a callback function in php. does anyone have any good examples of when/why you might use a callback?

[AyKay47]

in reality, all user-defined functions are callback functions..some defined functions allow for a function passed as an argument, and sometimes callback functions can be useful inside other functions...

 

here are some references..

http://www.sitepoint.com/forums/php-application-design-147/example-callback-php-336758.html

http://www.php.net/callback

[The Little Guy]

I am making a library, and I am not sure if some functions should have callbacks or not. I am not sure if it would be useful or not. Any suggestions?

[AyKay47]

hard to say without seeing your logic for the library...it really depends how you have your code setup..callback functions can be very useful if you would like to pass an argument from another function to the calling function

[The Little Guy]

Here is how I was planing on implementing a callback:

 

<?php
class TheCoolClass{
public $working = "";
function do_something($callback){
	$this->working = "I am doing something...";
	return call_user_func($callback);
}
}
$tcc = new TheCoolClass();
echo $tcc->do_something(function(){
return "hello";
});
echo $tcc->working;
?>

[AyKay47]

that would work but I do not see the reason for a callback function..

[The Little Guy]

that was just an example.

 

The problem I am having, is I don't know when a user would wan't to use a callback function. I can not think of a good example why I should let them use a callback in my code.

[trq]

I can not think of a good example why I should let them use a callback in my code.

 

Then you don't need them.