Rcpp call R optim (C++ code part)

// [[Rcpp::depends(RcppArmadillo)]]
#include <RcppArmadillo.h>
#include <string>


// [[Rcpp::export]]
Rcpp::List optim_cpp(Rcpp::Function obj_f, Rcpp::Function grad,
                    const arma::vec& initValue, const std::string& method) {
  Rcpp::Function Roptim("optim");
  return(Roptim(Rcpp::wrap(initValue), obj_f, grad, Rcpp::_["method"] = method));
}