Hello, here, we can read
" To calculate the Faddeeva function with relative error less than 10^(-r).
r can be set by the the user subject to the constraints 2 <= r <= 5."
I guess r corresponds to R in the funtion declaration
"Double_t Voigt(Double_t x, Double_t sigma, Double_t lg, Int_t R = 4)"
Could you put small “r” in the function declaration because now, R is a link to universal gas constant. SO if you put small “r”, link disappears and it is consitent with the documentation.

I tape now updated the source code changing from “R” to “r”. The documentation will then be updated in one of the next days.
Thank you for this report.