我有以下动作和功能。最终，我尝试在模板中访问value$processArtwork。一个选项是通过querystring传递值。然而，以下结果

"Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxx/europeanpaintings.rpc-staging.com/wp-includes/formatting.php:1021) in /home/xxxxx/mysite.com/wp-includes/pluggable.php on line 1228"

add_action(\'init\', \'process_artwork\');

function process_artwork(){
    if(isset($_GET[\'ss-process\'])) {

                $newUrl = "/process-artwork/?processedArtwork=56";

                wp_redirect( $newURL ); 
                exit;
    }
}