# ROS2 in 5 Days C++ **URL:** https://get-help.theconstruct.ai/c/course-support/ros2-in-5-days-c/62.md?page=1 [Latest](https://get-help.theconstruct.ai/latest.md) · [Categories](https://get-help.theconstruct.ai/categories.md) · [Tags](https://get-help.theconstruct.ai/tags.md) **Page:** 2 --- ## [Colcon Build Failed](https://get-help.theconstruct.ai/t/colcon-build-failed/19342)
**Author:** [@JordanEssman](https://get-help.theconstruct.ai/u/JordanEssman)\ **Replies:** 2\ **Last updated:** [September 21, 2022, 8:07am UTC](https://get-help.theconstruct.ai/t/colcon-build-failed/19342 "2022-09-21T08:07:00Z")
I am having an issues getting the topics\_25 tutorial to work in Unit 5. I get a colcon build failure: user:~/ros2\_ws$ colcon build --packages-select topics\_25 console cohesion+ \[0.255s\] WARNING:colcon.colcon\_core.packa… --- ## [Real Robot: Issue with local\_setup.bash](https://get-help.theconstruct.ai/t/real-robot-issue-with-local-setup-bash/15026)
**Author:** [@loickchovet](https://get-help.theconstruct.ai/u/loickchovet)\ **Replies:** 3\ **Last updated:** [September 15, 2022, 8:01am UTC](https://get-help.theconstruct.ai/t/real-robot-issue-with-local-setup-bash/15026 "2022-09-15T08:01:43Z")
Hello, I have finished the first parts of the tutorial and now trying to do the real robot project. I have 2 main issues : When I run the bridge according to the commands that are given, I still don’t see all the to… --- ## [Error: ld returned 1 exit status](https://get-help.theconstruct.ai/t/error-ld-returned-1-exit-status/19254)
**Author:** [@cjans121](https://get-help.theconstruct.ai/u/cjans121)\ **Replies:** 1\ **Last updated:** [September 15, 2022, 7:56am UTC](https://get-help.theconstruct.ai/t/error-ld-returned-1-exit-status/19254 "2022-09-15T07:56:49Z")
Getting the following error while compiling a package with the following source file. If I replace the code with the counter publisher example given in the course, it compiles fine. Could someone explain what’s the fix f… --- ## [Blocked callbacks? Need some help isolating issue in ros2 rosject please](https://get-help.theconstruct.ai/t/blocked-callbacks-need-some-help-isolating-issue-in-ros2-rosject-please/19229)
**Author:** [@reallen](https://get-help.theconstruct.ai/u/reallen)\ **Replies:** 4\ **Last updated:** [September 14, 2022, 8:29pm UTC](https://get-help.theconstruct.ai/t/blocked-callbacks-need-some-help-isolating-issue-in-ros2-rosject-please/19229 "2022-09-14T20:29:10Z")
I had some time on the real robot today and was trying to test my code. I have all of the parts of the ros2 project already implemented and tested in Sim. All of the behaviors work as they should in sim, but not so much … --- ## [ROS2 c++ project part 3 calling action server](https://get-help.theconstruct.ai/t/ros2-c-project-part-3-calling-action-server/19026)
**Author:** [@reallen](https://get-help.theconstruct.ai/u/reallen)\ **Replies:** 10\ **Last updated:** [September 9, 2022, 7:49am UTC](https://get-help.theconstruct.ai/t/ros2-c-project-part-3-calling-action-server/19026 "2022-09-09T07:49:16Z")
I’m currently on part 3 of the rosject that’s focused on actions. I was able to build the package with no errors, but I get this when I try to send a goal to the action server. Note: I understand that my code may not be … --- ## [ROS2 c++ real robot lab](https://get-help.theconstruct.ai/t/ros2-c-real-robot-lab/19075)
**Author:** [@reallen](https://get-help.theconstruct.ai/u/reallen)\ **Replies:** 1\ **Last updated:** [September 6, 2022, 4:19pm UTC](https://get-help.theconstruct.ai/t/ros2-c-real-robot-lab/19075 "2022-09-06T16:19:13Z")
I was trying to use the real robot lab yesterday but the stream was not reliable. I had a hard time properly testing anything. Would I be able to get more time slots for the week? Thank you --- ## [ROS2 cpp rosject part 2 help](https://get-help.theconstruct.ai/t/ros2-cpp-rosject-part-2-help/18947)
**Author:** [@reallen](https://get-help.theconstruct.ai/u/reallen)\ **Replies:** 3\ **Last updated:** [September 1, 2022, 10:05pm UTC](https://get-help.theconstruct.ai/t/ros2-cpp-rosject-part-2-help/18947 "2022-09-01T22:05:50Z")
I’m currently stuck on the second part of the rosject for the ros2 c++ in 5 days course. I’m subscribing to the /scan topic and have the state variables updated in the callback. I would like to use while loops to get the… --- ## [Unit 3 - Wrong references](https://get-help.theconstruct.ai/t/unit-3-wrong-references/18839)
**Author:** [@Gorgo](https://get-help.theconstruct.ai/u/Gorgo)\ **Replies:** 4\ **Last updated:** [August 30, 2022, 6:50am UTC](https://get-help.theconstruct.ai/t/unit-3-wrong-references/18839 "2022-08-30T06:50:48Z")
In unit 3.1 you claimed melodic and dashing are sourced, but most updated noetic and foxy are actually sourced in the script above. Plus in Unit 3.2 (Example 2) it asks for 4 shells, but 3 are actually used. UPDATE: I’… --- ## [Real Robot lab live stream not working for me](https://get-help.theconstruct.ai/t/real-robot-lab-live-stream-not-working-for-me/18812)
**Author:** [@reallen](https://get-help.theconstruct.ai/u/reallen)\ **Replies:** 3\ **Last updated:** [August 23, 2022, 8:39am UTC](https://get-help.theconstruct.ai/t/real-robot-lab-live-stream-not-working-for-me/18812 "2022-08-23T08:39:26Z")
Booked a session on 8/21/2022 from 7-7:25 but the livestream didn’t come on. Wondering if I could get some support on this. --- ## [Symbol Lookup Error in Example 1a and 3.1](https://get-help.theconstruct.ai/t/symbol-lookup-error-in-example-1a-and-3-1/15881)
**Author:** [@luckyljmever](https://get-help.theconstruct.ai/u/luckyljmever)\ **Replies:** 5\ **Last updated:** [August 22, 2022, 10:39am UTC](https://get-help.theconstruct.ai/t/symbol-lookup-error-in-example-1a-and-3-1/15881 "2022-08-22T10:39:59Z")
In example 1a and 3.1, in lesson 3 ros bridge, when running the bridge to route the “hello world” message from ROS1-\>ROS2, I got a symbol lookup error. The commands are run in separate terminals in the order: 1 . /home… --- ## [ROS2 Basics in 5 days C++, Custom Service Rosject](https://get-help.theconstruct.ai/t/ros2-basics-in-5-days-c-custom-service-rosject/17638)
**Author:** [@misbahsuhail123](https://get-help.theconstruct.ai/u/misbahsuhail123)\ **Replies:** 1\ **Last updated:** [May 31, 2022, 8:24am UTC](https://get-help.theconstruct.ai/t/ros2-basics-in-5-days-c-custom-service-rosject/17638 "2022-05-31T08:24:07Z")
In rosject wall following topic is working fine. But wall finding customized service .cpp file is unable to find service header file. It’s continously giving error "fatal error: my\_rosject/srv/find.hpp: No such file or d… --- ## [The IDE is not showing any files or folders](https://get-help.theconstruct.ai/t/the-ide-is-not-showing-any-files-or-folders/17488)
**Author:** [@mikebrascome](https://get-help.theconstruct.ai/u/mikebrascome)\ **Replies:** 2\ **Last updated:** [May 25, 2022, 7:51am UTC](https://get-help.theconstruct.ai/t/the-ide-is-not-showing-any-files-or-folders/17488 "2022-05-25T07:51:04Z")
I’m seeing the same issue mentioned here However, reloading the IDE is not fixing it. I’ve tried reloading several times and I’ve tried exiting back to Home and reopening the course. --- ## [ROS2 in 5 Days C++ ERROR in Unit 5](https://get-help.theconstruct.ai/t/ros2-in-5-days-c-error-in-unit-5/17274)
**Author:** [@roman.smid](https://get-help.theconstruct.ai/u/roman.smid)\ **Replies:** 3\ **Last updated:** [May 13, 2022, 8:04am UTC](https://get-help.theconstruct.ai/t/ros2-in-5-days-c-error-in-unit-5/17274 "2022-05-13T08:04:08Z")
I am getting this error when I want to echo the /counter topic Same error pops up when I want to pub on the topic. Any idea what that might be? --- ## [Unit 4: Exercise 4.1: Topic Publishers. I can't found '/count' topic](https://get-help.theconstruct.ai/t/unit-4-exercise-4-1-topic-publishers-i-cant-found-count-topic/16868)
**Author:** [@asrc](https://get-help.theconstruct.ai/u/asrc)\ **Replies:** 2\ **Last updated:** [April 27, 2022, 1:08am UTC](https://get-help.theconstruct.ai/t/unit-4-exercise-4-1-topic-publishers-i-cant-found-count-topic/16868 "2022-04-27T01:08:21Z")
Dear everybody, I have done all the steps in exercise 4.1 correctly, including: Create a new package named topic\_publisher\_pkg. Inside the src folder of the package, create a new file named simple\_topic\_publisher.cpp. … --- ## [Malformed Launch argument error Exercise 4.1](https://get-help.theconstruct.ai/t/malformed-launch-argument-error-exercise-4-1/16051)
**Author:** [@ianjchadwick](https://get-help.theconstruct.ai/u/ianjchadwick)\ **Replies:** 2\ **Last updated:** [March 10, 2022, 7:38pm UTC](https://get-help.theconstruct.ai/t/malformed-launch-argument-error-exercise-4-1/16051 "2022-03-10T19:38:42Z")
I keep running into this error: malformed launch argument 'topic\_publisher.launch.py', expected format '\:=\' after running this command to launch: user:~/ros2\_ws/src$ ros2 launch topic\_publisher\_pkg topic\_… --- ## [Unit 8 - package name 'gazebo\_msgs' was not found before](https://get-help.theconstruct.ai/t/unit-8-package-name-gazebo-msgs-was-not-found-before/15126)
**Author:** [@lgriera](https://get-help.theconstruct.ai/u/lgriera)\ **Replies:** 1\ **Last updated:** [February 1, 2022, 9:50am UTC](https://get-help.theconstruct.ai/t/unit-8-package-name-gazebo-msgs-was-not-found-before/15126 "2022-02-01T09:50:55Z")
Hello there, Is there anyone that comes across the following compilation error in Unit 8? \`user:~/ros2\_ws$ colcon build --packages-select bb8\_cpp\_unit\_3\_services Starting \>\>\> bb8\_cpp\_unit\_3\_services --- stderr: bb8\_cpp… --- ## [Unit 7: services](https://get-help.theconstruct.ai/t/unit-7-services/14837)
**Author:** [@ale.moreno991](https://get-help.theconstruct.ai/u/ale.moreno991)\ **Replies:** 1\ **Last updated:** [January 18, 2022, 9:57am UTC](https://get-help.theconstruct.ai/t/unit-7-services/14837 "2022-01-18T09:57:11Z")
I was wondering how to know gazebo model’s names? For example the tutorial uses: request-\>model\_name = “bowl\_2”; Then the student is supposes to use the gazebo/srv/DeleteModel to erase the table instead of the bowl. S… [Previous page](https://get-help.theconstruct.ai/c/course-support/ros2-in-5-days-c/62.md)