mirella melo's profile - activity

Hi.

I'm trying to use boost bind in my ROS 2 package. But I'm getting the following error when building with Colcon build:

error:‘_1’ was not declared in this scope

error:‘ _2’ was not declared in this scope

Here is my C++ code:

 #include <functional>
 #include <memory>
 #include "rclcpp/rclcpp.hpp"
 #include "std_msgs/msg/string.hpp"
 #include <message_filters/subscriber.h>
 #include <message_filters/synchronizer.h>
 #include <message_filters/sync_policies/approximate_time.h>
 #include <message_filters/time_synchronizer.h>
 #include "boost/bind/bind.hpp"
 #include <functional>

 void callback(const std_msgs::msg::String::SharedPtr& st_1, 
      const std_msgs::msg::String::SharedPtr& st_2) {
         // Callback function...
 }

 int main(int argc, char** argv){
     rclcpp::init(argc, argv);
     auto node = rclcpp::Node::make_shared("my_node");

     message_filters::Subscriber<std_msgs::msg::String> st_1(node, "st_1");
     message_filters::Subscriber<std_msgs::msg::String> st_2(node, "st_2");
     message_filters::TimeSynchronizer<std_msgs::msg::String, std_msgs::msg::String> sync(st_1, st_2, 10);
     sync.registerCallback(boost::bind(&callback, _1, _2));

    rclcpp::spin(node);

    return 0;
 }

CMakeFile:

 cmake_minimum_required(VERSION 3.5)
 project(project)

 # Default to C99
 if(NOT CMAKE_C_STANDARD)
     set(CMAKE_C_STANDARD 99)
 endif()

 # Default to C++14
 if(NOT CMAKE_CXX_STANDARD)
    set(CMAKE_CXX_STANDARD 14)
 endif()

 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
      add_compile_options(-Wall -Wextra -Wpedantic)
 endif()

 # find dependencies
 find_package(ament_cmake REQUIRED)
 find_package(rclcpp REQUIRED)
 find_package(std_msgs REQUIRED)
 find_package(message_filters REQUIRED)
 find_package(Boost REQUIRED COMPONENTS 
      system
      filesystem 
      date_time 
      thread
 )

 if(BUILD_TESTING)
     find_package(ament_lint_auto REQUIRED)
     ament_lint_auto_find_test_dependencies()
 endif()

 add_executable(sub src/subscriber.cpp)
 ament_target_dependencies(sub rclcpp std_msgs message_filters)
 target_include_directories(sub PRIVATE ${Boost_INCLUDE_DIRS})
 target_link_libraries(sub ${Boost_LIBRARIES})

 install(TARGETS
     sub
 DESTINATION lib/${PROJECT_NAME})

 ament_package()

Any help is welcome! Thanks!

Hi!

I'd like to use the OpenCV library in a C++ project - ROS2 (building with colcon build).

I added in the CmakeList the following command:

find_package(OpenCV 3.4.0 REQUIRED)

And when I #include any OpenCV header in my main code, I have no errors, but when I call any function of it, I have linking errors. It may be missing something in the CmakeList, but I don't know exactly what...

I appreciate any help. Thanks!

Hi.

I'm trying to use message_filters package (I also tried with image_transport...) to subscribe to two images. I couldn't understand the usage for ROS 2, but I found this short example for ROS 1. So, what changes do I need to do in this code to have it running in ROS 2?

Thanks in advance.

  using namespace sensor_msgs;
  using namespace message_filters;

  void callback(const ImageConstPtr& image, const ImageConstPtr& cam_info)
  {
       // Callback function...
  }

  int main(int argc, char** argv)
  {
         ros::init(argc, argv, "vision_node");
         ros::NodeHandle nh;

         message_filters::Subscriber<Image> image_1(nh, "image_1", 1);
         message_filters::Subscriber<Image> image_2(nh, "image_2", 1);
         TimeSynchronizer<Image, Image> sync(image_sub, info_sub, 10);
         sync.registerCallback(boost::bind(&callback, _1, _2));

        ros::spin();

        return 0;
  }

Hi. I`m trying to form the timestamp message in ROS2 (dashing) in python.

When I use

msg.header.stamp = node.get_clock().now()

I have the error:

The 'stamp' field must be a sub message of type 'Time'

Thanks in advance! :)

'

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For melodic, I simply removed anything related to the camera info file in the command line. rosrun camera_calibration c

Hi!

I`m trying to use a Rtabmap service, which is defined as follows:

 #request
 bool global
 bool optimized
 bool graph_only
 ---
 #response

Then, I call:

 ros2 service call /publish_map rtabmap_ros/srv/PublishMap "{global: 1, optimized: 1, graph_only: 0}"

But it returns:

Traceback (most recent call last):
File "/opt/ros/eloquent/bin/ros2", line 11, in <module>
    load_entry_point('ros2cli==0.8.7', 'console_scripts', 'ros2')()
File "/opt/ros/eloquent/lib/python3.6/site-packages/ros2cli/cli.py", line 69, in main
    rc = extension.main(parser=parser, args=args)
File "/opt/ros/eloquent/lib/python3.6/site-packages/ros2service/command/service.py", line 43, in main
    return extension.main(args=args)
File "/opt/ros/eloquent/lib/python3.6/site-packages/ros2service/verb/call.py", line 59, in main
    args.service_type, args.service_name, args.values, period)
File "/opt/ros/eloquent/lib/python3.6/site-packages/ros2service/verb/call.py", line 69, in requester
    module = importlib.import_module('.'.join(parts[:-1]))
File "/usr/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 994, in _gcd_import
File "<frozen importlib._bootstrap>", line 971, in _find_and_load
File "<frozen importlib._bootstrap>", line 955, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 665, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 678, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "/home/user/rtabmap_ros/install/rtabmap_ros/lib/python3.6/site-packages/rtabmap_ros/srv/__init__.py", line 1, in <module>
    from rtabmap_ros.srv._get_map import GetMap  # noqa: F401
File "/home/user/rtabmap_ros/install/rtabmap_ros/lib/python3.6/site-packages/rtabmap_ros/srv/_get_map.py", line 77
    self.global = kwargs.get('global', bool())
            ^
SyntaxError: invalid syntax

Please, any idea why this is happening?

Thanks in advance!

This makes sense! Hopefully, the Rtabmap team will fix it if this is the case. Thank you for your reply!!

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