[ros-users] Subscribing and publishing Topics

Hello,
I have some questions.

What i have to do if i get the warning:
"subscriber on'' destroyed immediately after creation. did you forget to store the handle"
how can i store handle?


The second question is,
if i subscribe a topic, i dont want to get every messages that arrives from that topic i have subscribed.
i want only get that one, that "now" received.

If the Callback function taking a while, the messages wich hass arrived while the Callback function is working, will stored in the quee, wenn the callback function has finished, the Callback function will called with the second messaged, but i want that it called with the last message that received:)

Thanks alot
Bünyamin