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
- func_get_arg() - 返回参数列表的某一项
- func_get_args() - 返回一个包含函数参数列表的数组
- ReflectionFunctionAbstract::getNumberOfParameters() - 获取参数数目
