I did this after 'make' for some C++ files, and then running one of them.
Does anyone know what the significance of the acronym 'TBD' is?
"TBD" usually means "To Be Determined". It was probably left as a placeholder in the code as a reminder to fill in missing functionality. The author may have meant it as a "To Be Done", which is a bit wrong but would still fit the general spirit of the acronym.