A brief analysis of the call user func() function in PHP and how to use call user func to call a custom function, callfunc_PHP tutorial

A brief analysis of the call user func() function in PHP and how to use call user func to call a custom function, callfunc

There is a function call_user_func in the UCenter source code, and I thought it was myself at first The result of the defined function cannot be found anywhere. Later I learned that call_user_func is a built-in function of PHP. This function allows users to call directly written functions and pass in certain parameters. Here is a summary of how to use this function.

The call_user_func function is similar to a special method of calling a function. The method of use is as follows:

<&#63;php
function nowamagic($a,$b) 
{ 
 echo $a; 
 echo $b; 
} 
call_user_func('nowamagic', "",""); 
call_user_func('nowamagic', "",""); 
//显示  
&#63;>

It’s strange to call the method inside the class. It actually uses array. I don’t know what the developer thought about it. Of course, new is omitted, which is quite innovative:

<&#63;php
class a { 
 function b($c) 
 { 
  echo $c; 
 } 
} 
call_user_func(array("a", "b"),""); 
//显示 
&#63;> 

The call_user_func_array function is very similar to call_user_func, except that the parameters are passed in a different way to make the structure of the parameters clearer:

<&#63;php
function a($b, $c) 
{ 
 echo $b; 
 echo $c; 
} 
call_user_func_array('a', array("", "")); 
//显示 
&#63;> 

The call_user_func_array function can also call methods inside the class:

<&#63;php
Class ClassA 
{ 
function bc($b, $c) { 
  $bc = $b + $c; 
echo $bc; 
} 
} 
call_user_func_array(array('ClassA','bc'), array("", "")); 
//显示 
&#63;> 

Both the call_user_func function and the call_user_func_array function support references, which makes them more functionally consistent with ordinary function calls:

<&#63;php
function a($b) 
{ 
 $b++; 
} 
$c = ; 
call_user_func('a', $c); 
echo $c;//显示 
call_user_func_array('a', array($c)); 
echo $c;//显示 
&#63;>
另外，call_user_func函数和call_user_func_array函数都支持引用。
view sourceprint&#63;
<&#63;php
function increment(&$var)
{
 $var++;
}
$a = ;
call_user_func('increment', $a);
echo $a; // 
call_user_func_array('increment', array(&$a)); // You can use this instead
echo $a; // 
&#63;>

The following will introduce how to use call_user_func to call a custom function

Use the call_user_func function to call 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 provided by the first parameter, the following parameters are the parameters of the custom function, and return the result of the custom function

function say($word)
{
 echo $word;
}
call_user_func('say', 'hello world'); //hello world
当然也可以调用类中的方法：
class A {
 function say($word = '')
 {
  echo $word;
 }
} 
$a = new A(); //注意，必须是要实例化的，除非是static
call_user_func(array($a, 'say'), 'hello world'); //hello world

2.mixed call_user_func_array ( callable $callback , array $param_arr )

It is said that call_user_func_array and call_user_func functions have the same function, but there are some differences 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
$a = new A(); //注意，必须是要实例化的，除非是static
call_user_func_array(array($a, 'say'), array('hello world')); //hello world

Note: The other two similar functions are call_user_method and call_user_method_array(), but they were discontinued and abandoned after PHP 4.1

http://www.bkjia.com/PHPjc/1068830.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1068830.htmlTechArticleA brief analysis of the call user func() function in PHP and how to use call user func to call a custom function, callfunc UCenter source There is a function call_user_func in the code, and I thought it was a self-defined function at first...