A brief analysis of the call user func () function in PHP and how to invoke a custom function _php instance using the called User func

Ucenter source code has a function Call_user_func, beginning to think it is a function of their own definition, the results are nowhere to be found. It was later learned that Call_user_func is a built-in function of PHP that allows the user to invoke a directly written function and pass in a certain parameter, summarizing the use of the function below.

The Call_user_func function is similar to a particular method of calling a function, using the following method:

<?php
function Nowamagic ($a, $b) 
{ 
 echo $a; 
 echo $b; 
} 
Call_user_func (' Nowamagic ', "", ""); 
Call_user_func (' Nowamagic ', "", ""); 
Show  
?>

Call the internal method of the class is strange, incredibly with array, do not know how to consider the developer, of course, save the new, also quite innovative:

<?php
Class A { 
 function B ($c) 
 { 
  echo $c; 
 } 
} 
Call_user_func (Array ("A", "B"), ""); 
Show 

The Call_user_func_array function is very similar to the call_user_func, except that it passes the argument in a different way, making the parameter structure clearer:

<?php
function A ($b, $c) 
{ 
 echo $b; 
 echo $c; 
} 
Call_user_func_array (' A ', Array ("", "")); 
Show 

The Call_user_func_array function can also invoke methods within the class:

<?php
Class classa 
{ 
function BC ($b, $c) { 
  $BC = $b + $c; 
echo $bc; 
} 
} 
Call_user_func_array (Array (' ClassA ', ' BC '), Array ("", "")); 
Show 

Both the Call_user_func function and the Call_user_func_array function support references, which tend to be more functional consistent with normal function calls:

<?php
function A ($b) 
{ 
 $b + +; 
} 
$c =; 
Call_user_func (' A ', $c); 
echo $c//Show 
Call_user_func_array (' A ', Array ($c)); 
echo $c//Display 
?>
In addition, both call_user_func functions and Call_user_func_array functions support references.
View Sourceprint?
<?php
function Increment (& $var)
{
 $var + +;
}
$a =;
Call_user_func (' increment ', $a);
echo $a; 
call_user_func_array (' Increment ', array (& $a));//can use this instead
echo $a;// 
?>

Here's an introduction to using Call_user_func to invoke custom functions

Using the Call_user_func function, you can call custom functions by passing in string functions and support references.

1.mixed Call_user_func (Callable $callback [, Mixed $parameter [, mixed $ ...]])

Invokes the custom function provided by the first argument, followed by the parameters of the custom function, and returns the result of the custom function

function say ($word)
{
 echo $word;
}
Call_user_func (' say ', ' Hello World '); Hello World
Of course you can also call methods in a class:
class A {
 function say ($word = ')
 {
  echo $word;
 }
} 
$a = new A (); Note that it must be instantiated unless it is a static
Call_user_func (Array ($a, ' say '), ' Hello World ');//hello world

2.mixed Call_user_func_array (callable $callback, array $param _arr)

In other words call_user_func_array and call_user_func function functions, just call the parameters a little different:

function A ($word)
{
 echo $word;
}
Class A {
 function say ($word = ')
 {
  echo $word;
 }
}
Call_user_func_array (' A ', array (' Hello World ')); Hello world
$a = new A ();/Note that must be instantiated unless it is a static
Call_user_func_array (Array ($a, ' say '), array (' Hello World)); Hello World

Note: The other similar two functions are Call_user_method and Call_user_method_array (), but they are deactivated after PHP4.1.