OpenCart：如何制作全局变量？

Question

I am trying to make two global variables within OpenCart. I basically want to be able to declare them in any of my .tpl files

<?php echo $global1; ?>

I have tried editing, library/system.php and also config.php by adding $global1="test" inside my files. However calling that in .tpl files is not working?

Example, look at the file below, I want to be able to call these variables anytime.. do I have to edit config.php or what?? The example shows the $header call which is used on every .tpl file.

not_found.tpl

<?=$header?>
<div class="breadcrumb">
<? foreach ($breadcrumbs as $breadcrumb) { ?>
    <? $breadcrumb['separator']; ?><a href="<?=$breadcrumb['href']?>"><?=$breadcrumb['text']?></a>
<? } ?>
</div>
<div id="content">
    <?=$global1?>
    <img src="/catalog/view/theme/default/image/error.png"/>
</div>
<?=$footer?>

Updated

/catalog/controller/common/header.php

<?php   
class ControllerCommonHeader extends Controller {


    protected function index() {

        // NEW GLOBAL VARS
        $cdnDefault="//www.gorgeouscouturedev.com/catalog/view/theme/";
        $currentUseLang = $this->language->get('code'); 

And now in /catalog/view/theme/default/template/common/home.tpl

<?=$header?>
<?=$column_left?>
<?=$column_right?>
<div id="content">

<? echo $cdnDefault ?>
<? echo $currentUseLang ?>

    <?=$content_top?>
        <div class="flexslider">
            <ul class="slides">
                <li><img src="catalog/view/theme/default/image/desktop.png"/></li>
                <li><img src="catalog/view/theme/default/image/blogger.png"/></li>
            </ul>
        </div>
    <?=$content_bottom?>
</div>
<?=$footer?>

And the errors:

 Notice: Undefined variable: cdnDefault in /catalog/view/theme/default/template/common/home.tpl on line 6
 Notice: Undefined variable: currentUseLang in /catalog/view/theme/default/template/common/home.tpl on line 7 

Answer 1

you can use $GLOBALS super global array

for example declare it first in controller/common/header.php

$GLOBALS["1"] = "test";

then use it in any tpl file like

<?php echo $GLOBALS["1"]; ?>

regarding that header thing, that header and five other files are actually declared in every controller file (corresponding to every tpl file ) like this

$this->children = array(
            'common/column_left',
            'common/column_right',
            'common/content_top',
            'common/content_bottom',
            'common/footer',
            'common/header'     
        );

Answer to updated question

/catalog/controller/common/header.php

<?php   
class ControllerCommonHeader extends Controller {


    protected function index() {

        // NEW GLOBAL VARS
     $GLOBALS["cdnDefault"]="//www.gorgeouscouturedev.com/catalog/view/theme/";
     $GLOBALS["currentUseLang"] = $this->language->get('code');

And now in /catalog/view/theme/default/template/common/home.tpl

<?=$header?>
<?=$column_left?>
<?=$column_right?>
<div id="content">

<? echo $GLOBALS["cdnDefault"]; ?>
<? echo $GLOBALS["currentUseLang"]; ?>

    <?=$content_top?>
        <div class="flexslider">
            <ul class="slides">
                <li><img src="catalog/view/theme/default/image/desktop.png"/></li>
                <li><img src="catalog/view/theme/default/image/blogger.png"/></li>
            </ul>
        </div>
    <?=$content_bottom?>
</div>
<?=$footer?>