I have created the package as asked in example 4.3. when asking for “rostopic echo /counter” the message “topic [/counter] does not appear to be published yet” appears. knowing that I have seen the echo(s) and its information of the previous unit of the same one(counter)>
Did you start publishing into /counter topic?
If you have already done publisher example, try running the publisher example in one webshell and then do rostopic echo in another webshell.
that has worked. one thing is that whenever I try to launch the topic subscriber launch file, this message appears: “ERROR: cannot launch node of type [topic_subscriber_pkg/simple_topic_subscriber]: Cannot locate node of type [simple_topic_subscriber] in package [topic_subscriber_pkg]. Make sure file exists in package path and permission is set to executable (chmod +x)”!
my launch file code is:
"
this line is already added in the CMakeLists.txt:
“add_executable(simple_topic_subscriber src/simple_topic_subscriber.cpp)
add_dependencies(simple_topic_subscriber ${simple_topic_subscriber_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
target_link_libraries(simple_topic_subscriber
${catkin_LIBRARIES}
)”