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Hi,
I have created a vector of type pair < int, int >, and now I'm trying to publish it on a ROS topic. The size of the vector is already known. How can I proceed ?
I have tried:
vector_pub = nh.advertise<std::vector<pair <int, int> > >("vector", 100);
vector_pub.publish(vector_node_position);
but it doesn't compile. Could you please help me?
Thanks :)
One way would be to create two custom messages, call them something like my_msgs/Pair.msg and my_msgs/VectorPair.msg. The contents would be:
my_msgs/Pair.msg
int a
int b
my_msgs/VectorPair.msg
my_msgs/Pair[] data
In your publishing node you would do:
#include <my_msgs/VectorPair.h>
vector_pub = nh.advertise<my_msgs::VectorPair>("vector", 100);
my_msgs Pair pair;
my_msgs::VectorPair vector_node_position;
pair.a = 1;
pair.b = 2;
vector_node_position.data.push_back(pair);
vector_pub.publish(vector_node_position);
Note that creating/populating the pair message and then pushing it into the vector message could happen inside a loop.
And if you'd like to avoid having to create the msg at the Publisher side, see ros/wiki/roscpp/MessageTraits. The Subscriber will still need the msg defs though.
I marked Thomas D's answer as the right one because I used it for reference, but if another newbie needs it, I think it's important to note that you have to change your CMakeLists.txt and package.xml :
In CMakeLists.txt:
find_package(catkin REQUIRED COMPONENTS ... message_generation ...)
...
add_message_files(
FILES
Pair.msg
VectorPair.msg
)
...
catkin_package(
INCLUDE_DIRS include
CATKIN_DEPENDS message_runtime
)
...
include_directories(include my_msg)
...
add_dependencies( your_executable ${PROJECT_NAME}_generate_messages_cpp )
And in package.xml:
<build_depend>message_generation</build_depend>
<run_depend>message_runtime</run_depend>
Thank you so much for your help!
Cheers
Asked: 2017-08-30 08:32:35 -0500
Seen: 1,881 times
Last updated: Aug 31 '17
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