Litle problem with assigning subscriber

Question

Hi. Sorry for all mistakes, English is not my native language. I have a subscriber that looks like this

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rclcpp::Subscription<minicar_control::msg::Feedback>::SharedPtr hw_feedback_sub;
...
hw_feedback_sub = this->create_subscription<minicar_control::msg::Feedback>("hw_feedback", 1000, std::bind(&STMRobotHW::feedbackCallback, this, _1));

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As far as I know this should work, but this is how problem looks in VS Code:

operand types are: std::shared_ptr<rclcpp::Subscription<minicar_control::msg::Feedback, std::allocator, rclcpp::message_memory_strategy::MessageMemoryStrategy<minicar_control::msg::Feedback, std::allocator>>> = std::shared_ptr<rclcpp::Subscription<const minicar_control::msg::Feedback &, std::allocator, rclcpp::message_memory_strategy::MessageMemoryStrategy<const minicar_control::msg::Feedback &, std::allocator>>>

I think, that this can be solved by removing hw_feedback_sub from header and use auto like this

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auto hw_feedback_sub = this->create_subscription<minicar_control::msg::Feedback>("hw_feedback", 1000, std::bind(&STMRobotHW::feedbackCallback, this, _1));

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But I want to know where I overlook mistake. Appreciate any help.

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Originally posted by Edvard on ROS Answers with karma: 95 on 2022-10-21

Post score: 0

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Original comments

Comment by ravijoshi on 2022-10-21:
The rclcpp::Subscription should be a class member. Removing it from header and using auto (the way you suggested), may avoid the error, but the callback will not be executed. On the other hand, I can not reproduce the error, as the code is incomplete. I suggest creating a minimal reproducible example

Answer 1

I manage to solve this problem. The issue was feedbackCallback method. Wrong version:

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void feedbackCallback(const minicar_control::msg::Feedback &fb_msg);

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Right version:

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void feedbackCallback(const minicar_control::msg::Feedback::SharedPtr fb_msg);

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@ravijoshi, thank you for your help. I didn't thought, that callback will not be executed.

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Originally posted by Edvard with karma: 95 on 2022-10-24

This answer was ACCEPTED on the original site

Post score: 0

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Original comments

Comment by ravijoshi on 2022-10-24:
I am glad you made it work. This is why I encourage creating a minimal reproducible example