Attention: Answers.ros.org is deprecated as of August the 11th, 2023. Please visit robotics.stackexchange.com to ask a new question. This site will remain online in read-only mode during the transition and into the foreseeable future. Selected questions and answers have been migrated, and redirects have been put in place to direct users to the corresponding questions on Robotics Stack Exchange. Additional details are available here.

How to send arrays with std_msgs/UInt8MultiArray and std_msgs/Float64MultiArray?

asked 2021-12-23 10:02:55 -0500

v.leto
44 ●11 ●15 ●26

Hi! I woul like to send arrays to a node, I've tried with this code, but I think there is something wrong when I try to copy the array values in the data structure...

uint8_t SSS_ground_unito[doppio_bins]={0};
immagine::pixel_ned messaggio;
double point_seabed_n[doppio_bins]={0};
double point_seabed_e[doppio_bins]={0};

//funzione per inviare il messaggio al nuovo nodo
void send_immagine(uint8_t SSS_grnd_unito[],double point_sbed_n[], double point_sbed_e[]){
    messaggio.pixel.data=SSS_ground_unito;
    messaggio.nord.data=point_seabed_n;
    messaggio.est.data=point_seabed_e;
    cout <<"send"<< messaggio.pixel.data<<endl;
    write_Out.publish(messaggio);//pubblica il messaggio sul topic 
    ROS_INFO("ping inviato");
 }

this is my msg

std_msgs/UInt8MultiArray  pixel
std_msgs/Float64MultiArray nord
std_msgs/Float64MultiArray est

edit retag flag offensive close merge delete

add a comment

1 Answer

Sort by » oldest newest most voted

answered 2021-12-26 01:54:23 -0500

robustify

956 ●10 ●25 ●18

The data fields of pixel, nord, and est are all std::vector, and must therefore have array elements allocated with either .resize() (see this) or by using .push_back() (see this).

Both ways will require your code to know how many array elements to expect in the input arguments to the send_immagine function. If you know there are N elements in the input arrays, you could use .resize(N) on each data field to allocate the required number of array elements, then copy each input array element into the corresponding vector element.

Alternatively, loop over the input array and call .push_back() once for each element.

edit flag offensive delete link

add a comment

Question Tools

2 followers

Stats

Asked: 2021-12-23 10:02:55 -0500

Seen: 280 times

Last updated: Dec 26 '21

How to send arrays with std_msgs/UInt8MultiArray and std_msgs/Float64MultiArray? edit

1 Answer

Question Tools

Stats

Related questions

How to send arrays with std_msgs/UInt8MultiArray and std_msgs/Float64MultiArray?