pejamide

I created the functions.php for my theme-child:

<?php
add_action('wp_enqueue_scripts', 'child_enqueue_styles',
  99);
function child_enqueue_styles(){
  $parent_style = 'parent-style';
  wp_enqueue_style($parent_style,
    get_template_directory_uri() . '/style.css');
  wp_enqueue_style('child-style',
    get_stylesheet_directory_uri() . '/style.css',
    array($parent_style));  }
if(get_stylesheet() !== get_template()){
  add_filter('pre_update_option_theme_mods_' .
    get_stylesheet(),
    function($value, $old_value){
      update_option('theme_mods_' . get_template(),
      $value);

      return $old_value;}, 10, 2);
  add_filter('pre_option_theme_mods_' . get_stylesheet(),
    function($default){return get_option('theme_mods_' .
      get_template(), $default);});}
/*---Initialize globald data ---*/  add_action('after_setup_theme', function(){
  $value1 = $GLOBALS['bbl_var1'];
  $value2 = $GLOBALS['bbl_var2'];
  $value3 = $GLOBALS['bbl_var3'];});
$GLOBALS['bbl_var1'] = 'JdV111';
$GLOBALS['bbl_var2'] = 'JdV222';
$GLOBALS['bbl_var3'] = 'JdV333';
?>

And my PHP-snippet:

<?php
echo '<br>' . $GLOBALS['bbl_var1'];
echo '<br>' . $GLOBALS['bbl_var2'];
echo '<br>' . $GLOBALS['bbl_var3'];

I got the PHP message:

Warning: Undefined array key "bbl_var1" in /......./wp-content/plugins/insert-php-code-snippet/shortcode-handler.php(100) : eval()'d code on line 2

What should I have done wrong?

2:
If I use three $GLOBALS[‘bbl_var1] = ‘111’, $GLOBALS[‘bbl_var] = ‘222’ and $GLOBALS[‘bbl_var3] = ‘333’, where and what I should put such initialization in functions.php?
And what should is code in a PHP snippet in order to read three $GLOABLS variables?

Thank you for your reponse, but I have two new questions:
1:
What and how I should use instead of $GLOBALS variables? Please give me two examples:
The one in functions.php for initialization of three variables (bbl_var1, bbl_var2 and bbl_var3) and

the other for PHP snippet in order to read three variables: bbl_var1, bbl_var2 and bbl_var3.

Where can I find ‘Trash’ in order to see if the “Snippet Preview” page is there?