Attention: Answers.ros.org is deprecated as of August the 11th, 2023. Please visit robotics.stackexchange.com to ask a new question. This site will remain online in read-only mode during the transition and into the foreseeable future. Selected questions and answers have been migrated, and redirects have been put in place to direct users to the corresponding questions on Robotics Stack Exchange. Additional details are available here.

Can constants in messages be changed without troubles with respect to "old" data?

asked 2014-07-10 02:37:21 -0500

Wolf

7555 ●71 ●105 ●162

Hi guys,

If I change (or add/remove) fields in message files "old" messages, e. g. record in bags, can no longer be subscribed by the node using the new message description, because md5sum and stuff do no longer fit...

Now my question: What happens if I add/remove/modify constant definitions ( http://wiki.ros.org/msg#Constants ) in messages? Will I still be able to use bags I recorded prior to the changes?

Thanks in advance, Wolf

edit retag flag offensive close merge delete

add a comment

1 Answer

Sort by » oldest newest most voted

answered 2014-07-10 14:19:08 -0500

tfoote

58457 ●128 ●550 ●526 http://www.ros.org/

You can add constants. If you remove or modify constants you will corrupt the data since the constant values are stored as the values.

Any of these will cause an MD5sum change and will require running a bag migration script to update the md5sum but it will not actually change the payload.

edit flag offensive delete link

add a comment

Question Tools

1 follower

Stats

Asked: 2014-07-10 02:37:21 -0500

Seen: 416 times

Last updated: Jul 10 '14

Can constants in messages be changed without troubles with respect to "old" data? edit

1 Answer

Question Tools

Stats

Related questions

Can constants in messages be changed without troubles with respect to "old" data?