Still a bit new to coding in WordPress but I'm left scratching my head on this...
After spending a number of hours tbshooting why only the first category was excluded when I called the get_adjacent_posts() like this:
$prevPost = get_adjacent_post(false,'30,31,32,410',true);
I opened up the code's core library link-template.php and find the delimiter for the exclude category list should be " and " so that now this actually works:
$prevPost = get_adjacent_post(false,'30 and 31 and 32 and 410',true);
On the codex pages for get_adjacent_post() and related get_next_post()/get_previous_post() functions this delimiter isn't documented from what I could see.
Is the " and " delimiter common practice in WordPress for delimiting category or tag IDs in functions? Seems like an odd delimiter not to be documented unless if I was more experienced I'd know this was common WP practice.
Thanks for any feedback on this one.