PHP 手册
后退 |  | 前进

# func_num_args

(PHP 4, PHP 5)

func_num_args -- Returns the number of arguments passed to the function

## Description

int func_num_args ( void )

Returns the number of arguments passed into the current user-defined function. func_num_args() will generate a warning if called from outside of a user-defined function. This function cannot be used directly as a function parameter. Instead, its result may be assigned to a variable, which can then be passed to the function.

> 注: 因为本函数依赖于当前域来决定参数细节，因此不能用作函数参数。如果必须要传递这个值，将结果赋给一个变量，然后传递该变量。

`<?php function foo() { $numargs = func_num_args(); echo "Number of arguments: $numargs\n"; } foo(1, 2, 3); // Prints 'Number of arguments: 3' ?>`

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

后退 | 起点 | 前进
func_get_args | 上一级 | function_exists