func_num_args

(PHP 4, PHP 5, PHP 7)

func_num_args — Returns the number of arguments passed to the function

说明

func_num_args ( void ) : int

Gets the number of arguments passed to the function.

This function may be used in conjunction with func_get_arg() and func_get_args() to allow user-defined functions to accept variable-length argument lists.

返回值

Returns the number of arguments passed into the current user-defined function.

更新日志

版本 说明
5.3.0 This function can now be used in parameter lists.
5.3.0 If this function is called from the outermost scope of a file which has been included by calling include or require from within a function in the calling file, it now generates a warning and returns -1.

错误／异常

Generates a warning if called from outside of a user-defined function.

范例

Example #1 func_num_args() example

<?php
function foo()
{
    $numargs = func_num_args();
    echo "Number of arguments: $numargs\n";
}

foo(1, 2, 3);   
?>

以上例程会输出：

Number of arguments: 3

Example #2 func_num_args() example before and after PHP 5.3

test.php
<?php
function foo() {
    include './fna.php';
}

foo('First arg', 'Second arg');
?>

fna.php
<?php

$num_args = func_num_args();
var_export($num_args);

?>

Output previous to PHP 5.3: 

2

Output in PHP 5.3 and later will be something similar to: 

Warning: func_num_args():  Called from the global scope - no function
context in /home/torben/Desktop/code/ml/fna.php on line 3
-1

注释

Note:

因为函数依赖于当前作用域以确定参数的细节，所以在 5.3.0 以前的版本中不能用作函数的参数。如必须传递此值时，可将结果赋与一个变量，然后用此变量进行传递。

参见

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