A brief analysis of the call user func () function in PHP and how to invoke a custom function using called user func, callfunc_php tutorial

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

Ucenter source code has a function Call_user_func, began to think that it is a function of their own, the results can not be found everywhere. Later I learned that Call_user_func is a built-in function of PHP that allows the user to call directly written functions and pass in certain parameters, the following summarizes the use of this function.

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

<?phpfunction nowamagic ($a, $b) {  echo $a;  Echo $b; } call_user_func (' Nowamagic ', "", ""); Call_user_func (' Nowamagic ', "", ""); Show  ?>

Call the method inside the class is rather strange, incredibly using an array, do not know how developers are thinking, of course, save the new, but also quite innovative:

<?phpclass a {  function B ($c)  {   echo $c;  

The Call_user_func_array function is similar to the Call_user_func, except that the parameter is passed in a different way, allowing the structure of the parameter to be clearer:

<?phpfunction A ($b, $c) {  echo $b;  

The Call_user_func_array function can also invoke methods within the class:

<?phpclass ClassA {function BC ($b, $c) {   

Both the Call_user_func function and the Call_user_func_array function support references, which makes them more functionally consistent with normal function calls:

<?phpfunction A ($b) {  $b + +;} $c =; Call_user_func (' A ', $c); echo $c;//Display Call_user_func_array (' A ', Array ($c)); EC Ho $c;//Display?> In addition, both the Call_user_func function and the Call_user_func_array function support references. View Sourceprint?<?phpfunction Increment (& $var) {$var + +;} $a =; Call_user_func (' increment ', $a); Echo $a; Call_user_func_array (' Increment ', array (& $a)); Can use this insteadecho $a; ?>

Here is a description of using Call_user_func to invoke a custom function

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

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

Call the custom function supplied by the first argument, followed by the parameter for the custom function, returning the result of the custom function

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

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

Words like Call_user_func_array and call_user_func functions, just a little bit different when calling parameters:

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 it must be instantiated unless it is Staticcall_user_func_array (array ($a, ' say '), array (' Hello World '); Hello World

Note: Another similar two functions are Call_user_method and Call_user_method_array () but after the PHP4.1, they are discontinued.

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