fix cxxwrap4

cxxwrap4/deps/src/hello.cpp

@@ -2,14 +2,26 @@
 #include "jlcxx/jlcxx.hpp"
 #include "jlcxx/stl.hpp"
 #include <Eigen/Dense>
-#include <string>
+#include <iostream>
+
+auto print_address(jlcxx::ArrayRef<double, 1> jlx) {
+  std::cout << jlx.data() << std::endl;
+  static jlcxx::ArrayRef<double, 1> y = jlcxx::make_julia_array(jlx.data(), jlx.size());
+  auto x = jlcxx::make_julia_array(jlx.data(), jlx.size());
+  std::cout << x.data() << std::endl;
+  // do something with x and pass results to y
+  for (size_t i = 0; i < jlx.size(); i++) {
+    y[i] = 2*x[i];
+  }
+  std::cout << y.data() << std::endl;
+  return y;
+}
 
 auto twice(jlcxx::ArrayRef<double, 1> jlx) {
   static Eigen::VectorXd y;
-  auto x = Eigen::Map<Eigen::VectorXd>(&jlx[0], jlx.size());
+  auto x = Eigen::Map<Eigen::VectorXd>(jlx.data(), jlx.size());
   // do something with x and pass results to y
   y = 2 * x;
-
   return jlcxx::make_julia_array(y.data(), y.size());
 }
 
@@ -21,21 +33,22 @@ void inplace_twice(jlcxx::ArrayRef<double, 1> jlx) {
 
 auto triple(jlcxx::ArrayRef<double, 1> v) {
   static Eigen::VectorXd y;
-  auto x = Eigen::Map<Eigen::VectorXd>(&v[0], v.size());
+  auto x = Eigen::Map<Eigen::VectorXd>(v.data(), v.size());
   // Do something
   y = 2 * x + x;
   return jlcxx::make_julia_array(y.data(), y.size());
 }
 
 auto inplace_triple(jlcxx::ArrayRef<double, 1> jlx) {
-  auto x = Eigen::Map<Eigen::VectorXd>(&jlx[0], jlx.size());
+  auto x = Eigen::Map<Eigen::VectorXd>(jlx.data(), jlx.size());
   x = 3 * x;
   for (size_t i = 0; i < jlx.size(); i++) {
     jlx[i] = x[i];
   }
 }
 
 JLCXX_MODULE define_julia_module(jlcxx::Module &mod) {
+  mod.method("print_address", &print_address);
   mod.method("twice", &twice);
   mod.method("twice!", &inplace_twice);