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I wonder why publisher publish a message. EX:
chatter_pub.publish(msg)
But the Subscriber CallBack function has a argument of pointer of msg. EX:
void chatterCallback(const std_msgs::String::ConstPtr& msg)
Link of above code: http://wiki.ros.org/roscpp_tutorials/...
A ConstPtr is the most efficient way to pass the message to your function, especially if it's a very large message. ros does support passing the message using other prototypes, but there's rarely a good reason to use any of them.
Hi sir, i know the reason why we use pointer. But why publish() just expect the msg( EX:std_msgs::String msg) instead of std_msgs::String::ConstPtr like a Callback function expect.
publish() takes a plain std_msgs::String to make writing code more convenient for you. It will also accept a ::Ptr or a ::ConstPtr message if that's what you have.
Asked: 2021-10-15 01:20:35 -0500
Seen: 386 times
Last updated: Oct 15 '21
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I've changed
messtomessage, as "a mess" is something completely different and rather confusing.When I first read your question title I assumed you had a problem with data corruption.
oh sorry for my bad english.Message is really the word i want to say. Thank you.
No problem.