Calling external C code to TwinCAT c++

Hallo

I know, how to include c - code into c++ using Extern "c".However,when i tried the same procedure in TwinCAT c++ to include external c - code it's saying Sytax error.
I used standard cyclic IO module from TwinCAT c++ and added some sample code named "source.h" and included this header file at Module1.cpp using Extern "c".
At the CyclicUpdate module included the function call(correct me if i'm wrong).
source.pngcyclicupdate.pnginclude.pngc++_c.jpg

i have attached the sample code and Error file as well.Please have a look.

I know solution could be very simple but i am unable to solve it.

Any suggestions would be appreciated.

Regards
venkat

Angehängte Grafiken

• source.png (12,2 KB)
• cyclicupdate.png (8,4 KB)
• include.png (5,5 KB)
• c++_c.jpg (23,8 KB)