Question about C-MEX S-function by S-function builder

I have successful experience of S-function builder with C source code. However, this time my source code is a .cpp file, and i met the error below. Can anyone give me suggestion about it? Thank you very much.

 Creating library C:\Users\zzhang\AppData\Local\Temp\mex_TA49Gc\templib.x and object C:\Users\zzhang\AppData\Local\Temp\mex_TA49Gc\templib.exp 
sfun_GHXmainMEX_wrapper.obj : error LNK2019: unresolved external symbol GHXfunction referenced in function sfun_GHXmainMEX_Outputs_wrapper 
sfun_GHXmainMEX.mexw64 : fatal error LNK1120: 1 unresolved externals 

C:\PROGRA~1\MATLAB\R2012B\BIN\MEX.PL: Error: Link of 'sfun_GHXmainMEX.mexw64' failed.