Scope of DEFINE variable in php

Question

Just a quick questions please, that I can't find the answer to.

If I define a variable like the below example:

DEFINE('THIS_TEST', 'ABC');

What is the scope of this? Could I then use this with in a class/object function:

public function testFunction() {
    echo THIS_TEST;
}

I have tried this in something similar but am not getting the results I was expecting, although this could be related to other issues.

Any advice would be appreciated.

i am using it as a EMAIL_FROM for phpmailer (extended), but the email is not being sent. so i wondered if the defined variable was available to the function without injecting it... and a quick google for the scope did not answer my question — Ford, Jan 07 '15 at 02:43
I'll bet you're probably getting `Parse error: syntax error, unexpected T_PUBLIC...` right? Remove the "public". Your code checks out without the "public" but threw the error when included. — Funk Forty Niner, Jan 07 '15 at 02:44
That issue is not caused by this. See [this answer](http://stackoverflow.com/questions/24644436/php-mail-form-doesnt-complete-sending-e-mail) for troubleshooting tips. — John Conde, Jan 07 '15 at 02:44
@Fred-ii- sorry, i am being lazy and have not got as far as looking the errors yet as i started to wonder (wanted to learn) the scope of a DEFINE variable first... + i only included an example which includes the "public function..." this is of course wrapped in a class — Ford, Jan 07 '15 at 02:45

score 4 · Accepted Answer · answered Jan 07 '15 at 02:43

4

You can read about scoping here.

Like superglobals, the scope of a constant is global. You can access constants anywhere in your script without regard to scope. For more information on scope, read the manual section on variable scope.

answered Jan 07 '15 at 02:43

Salvador Dali

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thanks, thats what i was looking for, could not find it for some reason.... its late here – Ford Jan 07 '15 at 02:54
yep, i also ran my own test too, but thought i would ask here as i could not find the details and find it better to know why things work rather than just knowing they do.... – Ford Jan 07 '15 at 03:01
Can you `define()` inside a class? Will it be accessive only via `$class_name->CONSTANT_NAME` or will it be super global? Also can you conditionally `define()` inside an `If` statement? – S. W. G. Jul 03 '23 at 14:06

score 3 · Answer 2 · answered Jan 07 '15 at 02:42

3

Assuming you actually mean the lowercase define(), this defines a constant (not a variable), which is available globally (with the exception of namespaces):

http://php.net/manual/en/function.define.php

answered Jan 07 '15 at 02:42

mopo922

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thanks, thats what i was looking for, could not find it for some reason.... probably as my inexperience called it a "defined variable" and not a constant. thanks! – Ford Jan 07 '15 at 02:54

Scope of DEFINE variable in php

2 Answers2