Is it possible in PHP to determine how many arguments a function requires?

Question

PHP

There is a function:

function func($arg1, $arg2) {
}
args_func(func); // должно вернуть 2

Answer 1

https://www.php.net/manual/ru/class.reflectionfunc...

function func($arg1, $arg2 = null) {}

$refFunc = new ReflectionFunction('func');
print $refFunc->getNumberOfParameters(); // 2
print $refFunc->getNumberOfRequiredParameters(); // 1

Answer 2

It is impossible to determine the number of parameters from out of context, because since version 5.6 support for a variable number of arguments has appeared variadic functions
Inside you can - func_num_args
ps so the best option is to parse the sources