Ah, that wasn't exactly the problem, but that lead me to figure out what the problem was. The problem was that I copied the code from my executable's CMakeLists.txt into my library, and I didn't change the target name, so it was telling me that EXEC_NAME didn't have a build target, because it was supposed to be LIBR_NAME. That resolved the linking with SFML issues, now I'm having issues where it's not able to link my library to my executable, but since that's not an SFML issue, I'll keep that outta here. Thanks for all your help everyone, much appreciated!