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. https://github.com/cran/fracdiff/tree/master/src if you open the fracdiff.h file you can see where to find the parts you are interested in..
Thanks to github :wink: