I cannot complile when using eig_sym from Armadillo

When i try to compile my code which uses eig_sym from Armadillo it gives this error

Undefined symbols for architecture x86_64:
  "_wrapper2_dsyev_", referenced from:
      void arma::lapack::syev<double>(char*, char*, int*, double*, int*, double*, double*, int*, int*) in main-df43f9.o
  "_wrapper2_dsyevd_", referenced from:
      void arma::lapack::syevd<double>(char*, char*, int*, double*, int*, double*, double*, int*, int*, int*, int*) in main-df43f9.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I am compiling using

c++ -std=c++14 main.cpp -o main

and if I delete the line where I use eig_sym it works fine, but it gives the same error also for other Armadillo's functions.