Filter ROS arguments before gflags parsing (#453)

Signed-off-by: Michael Carroll <[email protected]>

ros_gz_sim/src/create.cpp

@@ -49,15 +49,32 @@ DEFINE_double(Y, 0, "Yaw component of initial orientation, in radians.");
 // If these are not needed, just use the `gz service` command line instead.
 int main(int _argc, char ** _argv)
 {
-  rclcpp::init(_argc, _argv);
+  auto filtered_arguments = rclcpp::init_and_remove_ros_arguments(_argc, _argv);
   auto ros2_node = rclcpp::Node::make_shared("ros_gz_sim");
 
+  // Construct a new argc/argv pair from the flags that weren't parsed by ROS
+  // Gflags wants a mutable pointer to argv, which is why we can't use a
+  // vector of strings here
+  int filtered_argc = filtered_arguments.size();
+  char ** filtered_argv = new char *[(filtered_argc + 1)];
+  for (int ii = 0; ii < filtered_argc; ++ii) {
+    filtered_argv[ii] = new char[filtered_arguments[ii].size() + 1];
+    snprintf(filtered_argv[ii], sizeof(filtered_argv), "%s", filtered_arguments[ii].c_str());
+  }
+  filtered_argv[filtered_argc] = nullptr;
+
   gflags::AllowCommandLineReparsing();
   gflags::SetUsageMessage(
     R"(Usage: create -world [arg] [-file FILE] [-param PARAM] [-topic TOPIC]
                        [-string STRING] [-name NAME] [-allow_renaming RENAMING] [-x X] [-y Y] [-z Z]
                        [-R ROLL] [-P PITCH] [-Y YAW])");
-  gflags::ParseCommandLineFlags(&_argc, &_argv, true);
+  gflags::ParseCommandLineFlags(&filtered_argc, &filtered_argv, false);
+
+  // Free our temporary argc/argv pair
+  for (size_t ii = 0; filtered_argv[ii] != nullptr; ++ii) {
+    delete[] filtered_argv[ii];
+  }
+  delete[] filtered_argv;
 
   // World
   std::string world_name = FLAGS_world;