PHP const defined

Question

Why does the following code give me an exception saying that my constant isn't defined

MyClass::myFunction(MyClass::MY_CONST); // THIS GIVES THE ERROR   

// This is the class..
class MyClass {

    const MY_CONST = 'BLA';

    public static function myFunction($key) {
        if (!defined($key)) {
            throw new Exception("$key is not defined as a constant");
        }
    }
}

I've tried with

if (!defined($key)) {}
if (!defined(self::$key)) {}
if (!defined(__CLASS__ . $key)) {}

It is a matter of timing, so to speak. You are trying to use the constant before you define it. — Jay Blanchard
– Jay Blanchard, Commented Oct 27, 2014 at 12:23
While trying to write example code, I was wondering when would you use this? If MY_CONST wasn't defined, you wouldn't be able to use it in your first line — kero
– kero, Commented Oct 27, 2014 at 12:23

kero · Accepted Answer · 2014-10-27 12:26:18Z

2

You have to pass it as a string:

public static function myFunction($key) {
    if (!defined('self::'.$key)) {
        throw new Exception("$key is not defined as a constant");
    }
}


MyClass::myFunction('MY_CONST');

edited Oct 27, 2014 at 12:26

kero

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answered Oct 27, 2014 at 12:25

DarkBee

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Comments

LS11 · Accepted Answer · 2014-10-27 12:26:13Z

0

As Daniele D points out, for starts you're calling it with the value of the constant, not its name.

And defined needs a different syntax for the parameter when checking class constants, rather than defined constants. It should be

if (!defined('self::' . $key)) {

answered Oct 27, 2014 at 12:26

LS11

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Comments

AlexL · Accepted Answer · 2014-10-27 12:40:04Z

0

You need to pass the entire class name and constant as a string.

Like:

MyClass::myFunction('MyClass::MY_CONST');

answered Oct 27, 2014 at 12:40

AlexL

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