Thread: unresolved external symbol

I searched around a bit and found related topics, not sure if I am just not educated enough in this type of coding but I can not seem to identify where my link to the class and the call to functions are failing to link up. I got 11 of these errors all related to a function in the related .cpp file. Can anyone tell me why it would see the functions but not link to them properly? Thanks

Code:

SymbolScanner.obj : error LNK2019: unresolved external symbol SCAN_GetDecoderParams referenced in function "public: void __cdecl CSymbolScanner::SetI2O5DecoderLength(void)" (?SetI2O5DecoderLength@CSymbolScanner@@QAAXXZ)