Why not just use the WordPress get_query_var() function? WordPress Code Reference
// Test if the query exists at the URL
if ( get_query_var('ppc') ) {
// If so echo the value
echo get_query_var('ppc');
}
Since get_query_var can only access query parameters available to WP_Query, in order to access a custom query var like 'ppc', you will also need to register this query variable within your plugin or functions.php by adding an action during initialization:
add_action('init','add_get_val');
function add_get_val() {
global $wp;
$wp->add_query_var('ppc');
}
Or by adding a hook to the query_vars filter:
function add_query_vars_filter( $vars ){
$vars[] = "ppc";
return $vars;
}
add_filter( 'query_vars', 'add_query_vars_filter' );