Why are functions from an included file showing an error for undefined references?

[DMeye]

I'm using TrueStudio and I am getting an error on functions from another file. The file is in the Inc folder, is included in the project settings Path and Symbols, and my main has the #include (filename) at the top. Also, whenever I ctrl click on the functions, it takes me to the correct file, so it does know where the functions are defined. I'm new to this, but from what I researched the functions should be recognized. Thanks in advance!

[Tesla DeLorean]

Make sure you have marked each for inclusion with a define in stm32xyz_hal_conf.h

[DMeye]

Ahh found it! Like I said I'm new to this, but the functions had to be defined in the header file. It was from a library so I'm not sure why it wasn't there already, but regardless thanks for the help!