Hi, I'm giving a second look at your problem. What I don't get is why you get a link-time error for a function that should have been missing at compile-time already.
I put your sample code in essai.cc then compiled in two stages: $ g++ -Wall -c -o essai.o essai.cc (compilation) $ g++ -Wall -o essai essai.o -lntl (link) and everything worked, but I'm using the testing package for NTL, so that might explain things. Can you tell me what happens with the old package? Thanks, J.Puydt