func_num_args

Returns the number of arguments passed to the function (PHP 4, PHP 5)
int func_num_args ( )

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.

注意:

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.