PHP call_user_func vs. just calling function

Question

I'm sure there's a very easy explanation for this. What is the difference between this:

function barber($type){     echo "You wanted a $type haircut, no problem\n"; } call_user_func('barber', "mushroom"); call_user_func('barber', "shave"); 

... and this (and what are the benefits?):

function barber($type){     echo "You wanted a $type haircut, no problem\n"; } barber('mushroom'); barber('shave'); 

Answer 1

Always use the actual function name when you know it.

call_user_func is for calling functions whose name you don't know ahead of time but it is much less efficient since the program has to lookup the function at runtime.

Answer 2

Although you can call variable function names this way:

function printIt($str) { print($str); }  $funcname = 'printIt'; $funcname('Hello world!'); 

there are cases where you don't know how many arguments you're passing. Consider the following:

function someFunc() {   $args = func_get_args();   // do something }  call_user_func_array('someFunc',array('one','two','three')); 

It's also handy for calling static and object methods, respectively:

call_user_func(array('someClass','someFunc'),$arg); call_user_func(array($myObj,'someFunc'),$arg);