ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

Where is the message definition stored?

asked 2017-09-15 04:16:13 -0600

Mehdi. gravatar image

When a topic is advertised, are the md5 and the message definition of that message type stored somewhere accessible on the Ros server (By another node) or are they only sent with the message itself and checked every time a message is published?

Is there a way to get the message definition and the md5 without first receiving a message and without having to include the message header (working in c++)?

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2017-09-25 19:49:40 -0600

Dirk Thomas gravatar image

The message_definition is only exchanged when creating a TCPROS connection. For UDP transport there is no such information. Also the master doesn't store this information.

Depending on your scenario you might be able to load the message definition based on the topic type at runtime (in Python) if you can ensure that the system has the message package installed.

edit flag offensive delete link more

Question Tools



Asked: 2017-09-15 04:16:13 -0600

Seen: 472 times

Last updated: Sep 25 '17