Access compiled C code

Hello togehter,
I’m running RStudio Version 1.1.419 with R-3.4.3 on Windows 10.
I am trying to access compiled C functions. One example for that would be inside the fracdiff function. Looking into the fracdiff code there are two extern compiled C functions, called by .C("fracdf", all arguments) and .C("fdcov", all arguments). Apparently the main part of the calculation is done inside these C functions. I need to understand what is happening there. How can I see (even debug?) the exact calculation? I wasn't able to find the original non compiled source anywhere.
Thank you very much for your help!

Ok, I found it.
The original decompiled source can be looked up here at github. In my case you can find the fracdf and fdcov code in the fracdiff source. if you open the fracdiff.h file you can see where to find the parts you are interested in..
Thanks to github :wink: