publishing int variable

asked 2017-02-13 03:57:59 -0500

fafa
1 ●2 ●2 ●3

updated 2017-02-13 04:31:57 -0500

Hello,

I want to publish a variable, called targetIdx (type int), but I always get an error message

That's an extract of my publisher:

std_msgs::Int32 targetIdx;
targetIdx.data = targetIdx;
Sensor_Target_Nr_pub.publish(targetIdx);
ROS_INFO("Sensor Target Nr: %d", targetIdx.data);

That's the error message:

cannot convert ‘std_msgs::Int32’ to ‘std_msgs::Int32_<std::allocator<void> >::_data_type {aka int}’ in assignment
         targetIdx.data = targetIdx;

How can I solve the problem?

Thanks

I have declared the variable targetIdx as type int in the beginning of my program.

answered 2017-02-13 04:10:35 -0500

gvdhoorn
86574 ●283 ●1432 ●1054 http://cor.tudelft.nl/

updated 2017-02-13 04:11:06 -0500

std_msgs::Int32 targetIdx;

So targetIdx is declared to be of type std_msgs::Int32 here ..

targetIdx.data = targetIdx;

.. and here you assign the just instantiated msg to its own data member.

That is not going to work.

Could it be that you are shadowing your int targetIdx with the newly created std_msgs::Int32 targetIdx?

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Sorry I'm new to programming and ROS...could you please give me an example how to publish an int variable

fafa ( 2017-02-13 04:37:21 -0500 )edit

This is a C++ issue really, not a ROS issue.

You are creating a two variables with the same name. The compiler will only 'remember' the one that you created last. In this case that is the std_msgs::Int32 one, not the int.