Probably you made some error in that case, you’re building a web-site you have to take a deep breath and predispose yourself to the fact that you can make mistakes and have the WSOD. Anyway this so dreaded WSOD is something that appears also if you missed a semicolon somewhere, it’s nothing special, and appears because you have (reasonably when you’re not in development mode) the debug disabled. So the next time you see this WSOD open in local your wp-config.php change this line:
define('WP_DEBUG', false);
to
define('WP_DEBUG', true);
and upload it. Then you’ll see what kind of error you made and you can correct it easily.
Anyway the better solution would be testing changes in local.. but whatever.
Said that, no you don’t have to put that code in your child-theme, ’cause you missed a closing brace, and then you’ll have the WSOD. This is the code:
add_action('wp_head' , 'link_whole_slide');
function link_whole_slide() {
//sets the slider image link
add_filter('tc_slide_background' , 'my_slide_link', 10, 2);
function my_slide_link( $slide_image , $slide_link) {
//sets the slider image link
return sprintf('<a href="%1$s">%2$s</a>',
$slide_link,
$slide_image
);
}
}