PHP call_user_func() Function

The PHP call_user_func() function is used to call a user defined function or method, with the specified arguments.

Syntax

call_user_func(callback, args)

Parameters

`callback`	`Required.` Specify the function or method to be called. It can be an array, with the name of the class, and the method, or a string, with a function name.
`args`	`Required.` Specify zero or more parameters to be passed to the function.

Return Value

Returns the function result, or false on error.

Example: call_user_func() example

The example below shows the usage of call_user_func() function.

<?php
//defining a class with method
class foo {
  public function bar($arg1, $arg2) {
    echo __METHOD__." got $arg1 and $arg2 \n";
  }
}

//defining a function
function foobar($arg1, $arg2) {
  echo __FUNCTION__." got $arg1 and $arg2 \n";
}

//calling the foobar() function with 2 arguments
call_user_func("foobar", "one", "two");

// Call the $foo->bar() method with 2 arguments
$obj = new foo;
call_user_func(array($obj, "bar"), "three", "four");
?>

The output of the above code will be:

foobar got one and two 
foo::bar got three and four

Example: call_user_func() using namespace name

Consider the example below where describes how to use this function with namespace name.

<?php
namespace Foobar;

class Foo {
  static public function test($name) {
    print "Hello {$name}!\n";
  }
}

call_user_func(__NAMESPACE__ .'\Foo::test', 'John');
call_user_func(array(__NAMESPACE__ .'\Foo', 'test'), 'Marry');
?>

The output of the above code will be:

Hello John!
Hello Marry!

Example: using lambda function

The example below describes how to use this function with a lambda function.

<?php
$func = function($arg1, $arg2) {
  return $arg1 * $arg2;
};

var_dump(call_user_func($func, 5, 9));
?>

The output of the above code will be:

int(45)

Note: Callbacks registered with functions such as call_user_func() and call_user_func_array() will not be called if there is an uncaught exception thrown in a previous callback.

❮ PHP Function Handling Reference