On Thu, Feb 26, 2015 at 1:10 AM, jannik laval <[email protected]> wrote:
> Hi Dave, > > > > 2015-02-25 17:05 GMT+01:00 David T. Lewis <[email protected]>: > >> Hi Jannik, >> >> One other thing I just thought of: Check and see if your rostopic program >> is actually writing to standard output, as opposed to writing directly to >> /dev/tty. From a terminal window, I think you could do this: >> >> $ rostopic > out.txt >> > > Yes, it writes on the file after a ctrl-c. > Is that a hint? So if in one terminal you run $ rostopic > out.txt then without hitting ctrl-c, in another terminal view the contents of out.txt, is it empty? Do you get different behaviour with this between each of these mode [1]?... - *Latching mode* - rostopic will publish a message to /topic_name and keep it *latched* -- any new subscribers that come online after you start rostopic will hear this message. You can stop this at any time by pressing ctrl-C. *Once mode* - If you don't want to have to stop rostopic with ctrl-C, you can publish in *once mode*. rostopic will keep the message latched for 3 seconds, then quit. *Rate mode*. - In rate mode, rostopic will publish your message at a specific rate. For example, -r 10 will publish at 10hz. For file and piped input, this defaults to 10hz. Options: - -l, --latch New in Diamondback - Enable latch mode. Latching mode is the *default* when using command-line arguments. -r RATE - Enable *rate mode*. Rate mode is the *default* (10hz) when using piped or file input. -1, --once - Enable *once mode*. cheers -ben [1] http://wiki.ros.org/rostopic#rostopic_pub [2] http://answers.ros.org/question/59070/disable-latching-for-rostopic-in-piping-mode/
