Ros basics in 5 days, part 2, how to do service message?

1

in the assignment they say the message will have the following structure:
{
FindWall.srv

bool wallfound
}
but I am unsure what it means to have a findwall.srv in the beginning? in most of the other examples the request type is int32 or str or similar. I hope someone can explain this in detail so I know what to put in cmake etc. and how to proceed from here.

2

Hi @badmadafaka, weolcome to the comunity.
FindWall.srv is the name of the file .srv is the file extension supported by ros for service messages. as may already know a service message is composed of 2 parts, the request and the response divided by a
--- simbol, here is an example:

image
image819×141 5.85 KB

this is taken directly from the ROS SRV documentation.
check as well ROS msg and you will see that bool is a data type of ros.
So if you don’t need a response you can create your message as follows:

name of the file:
FindWall.srv

bool wallfound #request
--- # separator
# no response
3

Thank you for your reply. I think perhaps my copy paste left something out. Here is a screenshot of the message they want me to do:

Udklip
Udklip1382×533 23.8 KB

4

So it could be that findwall.srv is the name of the file, but in that case we have an empty request? Is that possible, and how would that work?

5

yes, that would work. try it out and tell me if you got any error.

6

ok, thanks for your assistance. And sorry for my juvenile name, I thought it was more private. LOL