cros's profile - activity

I have read the tutorial on webpage, but still don't know how to use it，special don't know how to write the funtion void callback( ). I hope someone could tell me how to write and use it more detailed. It's better if there are some examples.

I can't find ros cheat cheet ,where can I find it

I want to communicate ros program(just we write usually) and non-ros program(that means the program dosen't include the head file ros.h and anyother relate to the ros),I want the two programs can send and receive the date from each other. Are there any methods can do this work,or some ros API can be used to make the work easier. if you konw anyting about this please tell me ,thank you.

when I use the service,I found when the service called a number of times, it will appear the error

[ERROR] [1462436232.811787210]: accept() on socket [6] failed with error [Too many open files]

also have the error I don't know why and how to fix it.if someone knows the reason,please tell me ,thank you very much

we know that rosbridge can communicate with the javascript,I want to konw if there is a c++ api can achieve the same function.

yes，have image data

when I let numbers of machines use the same master,the running speed is very slow. such as I have three computers A B and C. Then I running the roscore in the C, let the A and B use the the master in the c at the same time.I found the speed of public and subscribe topics is very slow, so as the services. I don't why and how to solve the problem. if sameone knows please tell me. thank you very much.

when I download the packages rbx1 and move_base in the same workplace( I do this following the book ros_by_example_hydro chapter eight ), then I want fire up a node named move_base from a launch file in the rbx1,but has an error,that's why

I just use one machine

I find the same problem always appear when numbers of computers share the one master, but I just in one computer publish and subscribe the message ,why I have the same problem.

when Running ROS across multiple machines ,it can share master for two machines,but when run a node ,it appear something like Couldn't find an AF_INET address for [hostname],I don't know why. when I run a node in machine a,it pub a topic named "message",but I can't sub the "message" for a node from machine b,but when I use "rostopic list ",it has the topic named "message"

I can compile the ros node in eclipse,but I don't know how to run the node,if anyone know how to do it ,please tell me ,thank you very much.