Can you assign values to constants with equal sign after using defined in php?

Question

I know to define a constant, you do something like this

define("CONSTANT", "Hello world.");

if I want to change the value of the constant I would have to do define() again? Why couldn't I just do CONSTANT = "whatever"; after it has already been defined the first time?

Answer 1

The whole point of a constant is that it is constantly and always the same. You can not change a constant after you defined it.

Even using define("CONSTANT", "Hello world."); would return an error.

I just did it real fast to show you what you'd get:

Notice: Constant CONSTANT already defined in /Users/stokholm/test.php on line 3

Call Stack:
    0.0003     629992   1. {main}() /Users/stokholm/test.php:0
    0.0171     630232   2. define() /Users/stokholm/test.php:3

Answer 2

Constants, as the name specifies, cannot be changed once defined. Use variables instead.