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PHP global variable is undefined inside a function even if global keyword is used

Posted by: admin December 1, 2021 Leave a comment

Questions:

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

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 😛 )

Answers:

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.

###

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.