@muldjord Weird, I thought I did put it under that thread.
Anyways, I couldn't help with c++ unfortunately.
However they do mention API's, but I'm not sure how to find them on their site. https://emumovies.com. Sorry, I'm not much help.
Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first