My function doesn't work into WordPress but outside, it works - what am I missing?

Question

I used a functions into my page I created for WordPress, it's working, but the functions 're not working, doesn't showing any result. For example:

<?php
function tester()
{

global $pol;

$pol="ok all fine and working";
}

tester();

echo $pol;
?>

This function works perfectly if I use it outside WordPress, but problem is when I tried using it into the file I created, it won't work.

I don´t know what the difference I need to assure to work it in WordPress other than any other PHP file.

Answer 1

WordPress template files are included via functions, which places the scope of those included files within those functions. That's why you have to declare it global twice. Here is an example you can try with 3 simple php files to illustrate this without using WordPress:

main.php

function include_file_1(){
    include '1.php';
}
function include_file_2(){
    include '2.php';
}
include_file_1();
include_file_2();

1.php

function tester(){
    global $pol;
    $pol="ok all fine and working";
}

2.php

tester();
echo $pol;

If you test this out, you will see you get nothing from echo $pol, it's not within scope. Now edit 2.php to declare global $pol first:

global $pol
tester();
echo $pol;

And now you get the expected results.

Answer 2

It's a PHP question. That's because you do not use correct way to retrieve your global. Use the magic var_dump instead:

global $pols;
var_dump($pol);

You could also use :

$GLOBALS['$pol'] 

And then :

echo tester();

Answer 3

To use a global you need to declare it global before defining it and then pull it into scope with global $var_name before using it. You did not do that. You only did half of it.

function tester()
{
    global $pol;

    $pol="ok all fine and working";
}
tester();

global $pol;
echo $pol;

But why are you using a global at all? Why not just return the value? Your code will be shorter and neater.

function tester()
{
    return "ok all fine and working";
}
echo tester();