call_user_func_array to not accept unexpected function parameters

Question

I have a function which accepts no parameters, i.e. function doSomething(){...}.

If I run, call_user_func_array('doSomething', array('param1' => 'something')); it doesn't return an error.

Can I make it force an error like, "This function should not accept parameters".

Sure, just check via func_num_args() and throw an Exception if needed — kero
– kero, Commented Mar 7, 2015 at 16:27
BTW: It is completely irrelevant how you call the function, directly or with call_user_func() doesn't make a difference. — Ulrich Eckhardt
– Ulrich Eckhardt, Commented Mar 7, 2015 at 17:43

Mark Baker · Accepted Answer · 2015-03-07 16:29:59Z

1

It's perfectly possible to send more parameters to a user-defined function than the function signature defines. That's because you can use additional code within your function to handle these, or simply ignore them.

function doSomething(){
    if (func_num_args() > 0) {
        throw new Exception('Too many arguments');
    }
    ....
}

Use something like the above to test the arguments that have been passed to your function

answered Mar 7, 2015 at 16:29

Mark Baker

213k34 gold badges354 silver badges390 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Stefan Dunn Over a year ago

I looked into this, but with a lot of functions it would be great not to have to do it for all all functions. Maybe I could check number of accepted arguments before calling call_user_func_array?

Mark Baker Over a year ago

call_user_func_array('doSomething', array('param1' => 'something')); isn't conducive to checking the args in the array whenyou're defining the array in the actual call and not beforehand.... but why is it such an issue? If it's your code doing the call, then you control what gets passed to the function

Stefan Dunn Over a year ago

I want to alert the user that the function does not accept parameters.

Mark Baker Over a year ago

Is this a library that you're writing for others? If so, what's wrong with good documentation identifying the parameter arguments that can be passed, and the fact that any additional parameters will simply be ignored

Ulrich Eckhardt Over a year ago

Starting with PHP 5.6, I believe, functions can now actually declare explicitly that they take a variable number of arguments, making this stupid hack using func_get_args() obsolete. Just wanted to mention this small, related detail.

|

l'L'l · Accepted Answer · 2015-03-07 16:31:12Z

1

You could use func_num_args:

function foo()
{
    $n = func_num_args();
    if ($n > 0) {
        echo "Number of arguments: $n, 0 expected.";
    return;
    }
}

foo(1, 2, 3);

:: Info

answered Mar 7, 2015 at 16:31

l'L'l

47.5k12 gold badges102 silver badges154 bronze badges

Comments

Ulrich Eckhardt · Accepted Answer · 2015-03-07 17:19:52Z

0

Check out the ReflectionFunction class. Using that, you can detect how many parameters a function expects and avoid calling it on mismatch.

answered Mar 7, 2015 at 17:19

Ulrich Eckhardt

17.7k5 gold badges31 silver badges63 bronze badges

Collectives™ on Stack Overflow

call_user_func_array to not accept unexpected function parameters

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

7 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related