PHP函数实际参数

Question

我怎么知道函数的实际参数数量,

我知道func_num_args返回函数内传递的args的数量,但是外面怎么样？

function foo($x,$y)
{
// any code
}

我怎么能动态地知道绑定到该函数的实际数量的args

Answer 1

i take it from SO answer : PHP function to find out the number of parameters passed into function?

func_number_args() is limited to only the function that is being called. You can't extract information about a function dynamically outside of the function at runtime.

如果您尝试在运行时提取有关函数的信息,我建议使用Reflection方法:

if(function_exists('foo'))
{
 $info = new ReflectionFunction('foo');
 $numberOfArgs = $info->getNumberOfParameters(); // this isn't required though
 $numberOfRequiredArgs = $info->getNumberOfRequiredParameters(); // required by the function

}