Subscriber issue

asked 2013-03-18 23:33:16 -0600

camilla
255 ●48 ●54 ●60

What should I do if I want that the callBack function of a subscriber returns a value. In particular I have a subscriber that receive sensor_msgs/Range and I want the callBack function to return the range value that is in the message but I don't now how to implement it.
Any suggestion?

Thanks in advance

edit retag flag offensive close merge delete

add a comment

1

answered 2013-03-19 01:33:58 -0600

dornhege

31395 ●134 ●284 ●498

Callback cannot return values.

Where would you want to have that value returned to?

edit flag offensive delete link

Comments

You could take an example from the talker tutorial, to communicate to the sender of the original message.

aimc ( 2013-03-19 01:47:30 -0600 )edit

That's what services are for.

dornhege ( 2013-03-19 02:28:12 -0600 )edit

I want it returned in the main where I declare the subscriber

camilla ( 2013-03-19 04:56:59 -0600 )edit

You just want to have the message value available in the main? You could write it to a global variable or better use boost::bind for the callback and pass in a reference to the value to write to.

dornhege ( 2013-03-19 06:00:23 -0600 )edit

add a comment

1

answered 2013-03-18 23:41:03 -0600

Victor_ocv2
483 ●12 ●17 ●25

updated 2013-03-19 07:49:01 -0600

If you just want to get the value, declare the callback as member function of a class. Then, you can write the received data into that class, in example (pseudocode):

void Robot::LaserCallback(const sensor_msgs::LaserScan::ConstPtr& msg){

for ( range_data in msg) {
    this->rangedata = msg->ranges
    }
}

In this way from your main you could just call a get method to obtain the latest data available.

edit flag offensive delete link

add a comment

Subscriber issue

2 Answers

Comments

Question Tools

Stats

Related questions

Subscriber issue edit

2 Answers

Comments

Question Tools

Stats

Related questions

Subscriber issue