18

Yes I know global variables is a bad practice, but ease up on that rule for this one :P

My code:

include('something.php'); //where $from is declared

function myfunc() {
    global $from;
    echo "from(myfunc)=$from<br />";
    ...
}

echo "from=$from<br />";
myfunc();

The result is:

from=2010-05-01
from(myfunc)=

What's going on? :(

EDIT: If it helps, all the code above is inside a view file in CodeIgniter ( and yes, I know functions are not supposed to be inside views :P )

1
  • 1
    I tested it and it works fine (after adding a semicolon after the echo) on PHP 5.3.1.
    – Harmen
    Commented Jul 7, 2010 at 10:16

2 Answers 2

27

I'll bet a beer you are not inside the global scope with this snippet. Are you calling this from within a function?

In that case, the $from you define in something.php is not global, while the one you reference in the function is.

It will probably work if you add a global $from; inside something.php before you define $from.

Needless to say, it's not a nice practice either way, and you should follow Gordon's advice.

2
  • Hi Pekka, you're right. I added $GLOBALS['from'] = 'value' outside the function, and the value was found inside myfunc(). I didn't realize this page was generated by CodeIgniter's $this->load->view() function. Thanks!
    – Obay
    Commented Jul 7, 2010 at 10:27
  • 13 years later ... I've just used IIFE in a legacy code base exactly to isolate globals and it did not even occur to me that I actually needed global scope for globals to work as expected, lol.
    – dakujem
    Commented Jul 12, 2023 at 16:52
17

Do yourself a favor and use Dependency Injection.

function myfunc($from) {
    return "from(myfunc)=$from<br />";
}
$from = '2010-05-01';
echo myfunc($from);

Doing so will make your code more maintainable, less coupled and more easily unit-testable because it is isolated from the global scope. Plus, when you do it people think you are cool.

2
  • 6
    +1 I've never realized I can say "I've being doing dependency injection since 2002" :)
    – Pekka
    Commented Jul 7, 2010 at 10:25
  • Thanks, I'll be using Dependency Injection instead :P
    – Obay
    Commented Jul 7, 2010 at 10:36

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