Questions tagged [std-msgs]

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ROS2 Serial Communications

I am trying to get some data out from the proximity sensor through USB UART converter. I don't know why but when I just run the code on mac OS with the similar code, it perfectly works fine. I would ...
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Is there any difference between example_interfaces and std_msgs?

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Why ros2 std_msgs/Header removes `seq`?

Hi, I'm upgrading a ros1 package to ros2 and found that std_msgs/Header msg has changed. in ros1: https://github.com/ros/std_msgs/blob/kinetic-devel/msg/Header.msg <...
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std_msgs/Float32.h not found

Hi, I am relatively new to trying to do anything with c++ in ros, so I'm sorry if this is a stupid question. I am trying to get AMCL to publish max weight. The plan is to publish it to a float 32 ...
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[ROS2 Humble] Segmentation Fault for assigning Header/Frame ID to shared pointer

Hi Community, i am currently struggling with some segmentation fault which i don't understand while assigning the Frame ID to the header of a Odometry Message ...
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how can I make a custom msg struct to publish?

i have a script that publishes a lot of system information like battery voltage/current, sysstem status, and isready all in all i have 13 different parameters im publishing. what i want is to tie all ...
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[ROS2] publishing UInt16

Hi, I would like to publish a message without it being of type std_msgs::msg::String. ...
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Header stamp: When is/should this be from?

Many messages in ROS include the header, which includes the timestamp. What is best/expected practice for this? Should the stamp be the time at which the message is sent or the time of the event it is ...
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Packages roscpp and std_msgs

In tutorials of wikiros, roscpp, rospy and std_msgs become dependencies of our newly-created package. What I am wondering is what they provide for us. For example, I am writing a node, and in this ...
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Cannot build simple service on Melodic (getServerMD5Sum is not a member of std_msgs::Float32)

I'm having problems compiling a simple ROS service. I'm using a fresh install of Ubuntu 18.04.3 - ROS Melodic. Ive simplified down the project as much as I can to replicate the problem. My project ...
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Not able to publish image to std_msg/Image

I am trying to run a publisher code that publishes an Image to a topic. But, whenever I run the code, I get an error. The code I have written is below - ...
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ros msg definitions, difference between std_msgs/TYPE and type

Hello, What is the difference in between using std_msgs/Float32 someVariable and float32 someVariable in msg files? I noticed ...
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Sending multiple Float64 messages to different topics

Is it possible to send multiple Float64 messages to different topics from the same Float64MultiArray, for example? Meaning, can I create a Float64MultiArray message and publish each element in the ...
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Why Empty message in std_msg?

As in the title, I don't understand why is there an Empty type in std_msgs? What is it used for? Thanks! Originally posted by ...
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Float32MultiArrary publish

The following code subscribes pose information and then it calculates inverse kinematics so that theta1, theta2, and theta3 are acquired. I would like to publish this theta1, theta2, and theta3 with ...
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How to Initialize a 2D MultiArray?

Hello, I am using a Raspberry Pi with Lubuntu 16.04, ros Kinetic, a Sick tim 561 and the package sick_scan to get data from the tim561. Currently my goal is to extract the x and y data from the ...
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How to work with std_msgs::Int16MultiArray message type?

What is needed to publish a How to work with std_msgs::Int16MultiArray message? I tried std_msgs::Int16MultiArray msg; int16_t *velocities; msg.data = velocities; ...
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std_msgs types and 'normal' type

Hi I want to display a variable on a topic. Therefore I need to transform my variable from an volatile unsigned long to an std_msgs type (for example UInt64). This gives following error: ...
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Unable to push_back float64 custom msg in std::vector<std_msgs::Float64>

I have a custom message as follows: sensor_msgs/PointCloud2 velodynepoints float64[3] velodynenormal and a subscriber nodelet with the following callback function ...
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custom message fails to build; no such file or directory

I followed the custom message documentation to the letter, and searched all the related questions on here, and unfortunately I am still stuck. Could you please have a look? I am getting the same error ...
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catkin_make fails: /opt/ros/kinetic/include/std_msgs/Float32.h errors

I've installed ROS Kinetic from source on Debian 9 running on the BeagleBone Blue. I can run roscore and successfully create a workspace. I'm trying to create a node/package that will control the ...
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Problem with data from subscriber not going anywhere

Related question: https://answers.ros.org/question/278181/issues-with-seg-faults-and-node-not-publishing-anything/ In my code there are two subscriber functions. I want to pass the shared pointer data ...
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Is there an easy way to publish std_msgs::Time from cli?

I'd like to publish the current ROS time to a topic from the command line. Is there some way to achieve this? EDIT: Focusing my question a bit more-- I'd like to publish the equivalent of ros::Time::...
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error: no match for 'operator='

Hey, I get this error when building the package: ...
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1 answer
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common-msgs vs std-msgs?

When various message handling packages like actionlib, navigation, sensor, geometry are included in the common_msgs stack, why is std_msgs package separated? How is std_msgs package different from the ...
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Why doesn't std_msgs::Float32MultiArray have a Header field?

Some messages (e.g., sensor_msgs::PointCloud2) have Header fields, while many others don't. In particular, why don't float32 multiarrays (or any other std_msg/ messages) have header fields? Why was ...
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setting each bit in std_msg::Int8 rather the whole byte?

I at the moment trying to come up with a solution such that I can set my std_msgs::Int8 bitwise instead of setting the whole byte. The reason why i want to do that is because, i am currently using the ...
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genmsg.base.InvalidMsgSpec: array is not a legal constant type

According to http://wiki.ros.org/msg, "With the exception of time and duration, you may declare any built-in type as a ...
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Subscribing to a Bool msg via rosserial_arduino

Hello All! I'm in the process of building a tool for a robot that I'm working with and we are trying to use an Arduino to communicate with ROS to control the end effector. We are right now ...
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Hi guys. I have built ROS from source on my PI 2 but I am unable to import libraries

I am not being able to import even the basic libraries such as with from std_msgs import Stringsin my python scripts. Please help me fix this issue. EDIT This is my ...
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What does `Int32MultiArray.layout.data_offset` mean

Here's the contents of Int32MultiArray.msg: ...
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Push vector into `MultiArray`-Message and publish it

I simply try to push multiple vector<double> into the message format, but can not figure it out also I looked at this and this. ...
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How do I use rqt_plot to subscribe to std_msgs

I do have an Array from #include "std_msgs/Float64MultiArray.h" and it is constituted as followed: ...
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Convert from Int32MultiArray into vector (roscpp)

How to simply put array from the std_msgs into vector<double> ...
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How to compile the listener.cpp and talker.cpp without cmake

Upon reading the following tutorial Simplest ROS tutorial, I wanted to compile the listener.cpp and talker.cpp given here. I am using the following command, as directed by the tutorial: ...
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get std_msgs::Header associated with a frame from image_transport?

Is there a way to get the std::msgs::Header associated with an image sent over image_transport? I need some unique key from my images to stick in the header of mesages derived from them to maintain ...
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Basic Int32 and std_msgs question

I'm very new to working in Ros. I am trying to figure out how to read from a bag file and so I'm interested in making a small bag file for testing purposes. I have wrapped the code for writing the ...
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1 answer
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Building std_msgs from source fails

Hello all. I am (attempting) to build ROS Jade from source on Gentoo. I am now at 116 targets built. For some reason, I'm struggling with std_msgs. ...
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2 answers
34 views

Create a std::vector of msgs

Hello all, I'm trying to create a vector of a custom msg that I have declared. The msgs contains the following line: ...
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ROS Arduino message type restrictions?

I'm getting a 'mismatched protocol' error when publishing a message (UInt8) from an Arduino to ROS: Mismatched protocol version in packet: lost sync or rosserial_python is from different ros release ...
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Callback from subscriber does not work

Hi. This is probably an insignificant problem, but I just can't see it. I used the publisher/subscriber tutorial to make communication in my own program. The publisher publish well in a topic, and the ...
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rosjava nodes isolated and ros tools buggy behavior

I'm trying to connect the android pubsub tutorial of android_core with a master core in my server. https://github.com/rosjava/android_core/tree/indigo/android_tutorial_pubsub I'm using ros indigo, ...
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What is the proper way to obtain the fixed-axis covariance matrix from quaternions?

REP 103 defines the standard for rotation representation as quaternions, but the covariance matrix associated to it is given in terms of fixed axis rotations. In my work, I use quaternions directly ...
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Warning on advertise of std_mgs/Empty

Recently (maybe since some update...), whenever I advertise a topic of topic std_msgs/Empty I receive WARNING: Advertising on topic [/topic_name] with an empty message definition. Some tools (e.g. ...
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2 answers
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a question about Float64MultiArray

Hi everyone I define my Variable as follow: std_msgs::Float64MultiArray Atest; I want to assign a value to specific element. for example i want to change value of fifth element to 5. how i can write ...
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Using if statements with std_msgs::String::ConstPtr

I have a node that is getting action calls from another node. Once it gets the action, I want to call a specific function but the if statement doesn't ever return true. How can I get an if statement ...
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accessing std_msgs::Float64MultiArray data

I have a 2D Eigen matrix MatrixXd map = MatrixXd::Zero(mapSizeX,mapSizeY); I read data from a text file and update the matrix, which works fine. ...
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What is the proper way to create a Header with python?

I seem unable to find what the proper procedure is to fill a std_msgs/Header field in a message using python. I have found this for C++: my_message message; // using a std_msgs/Header called header ...
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roscreate-pkg problem

I'm following the tutorial on ros.org and I have a problem with this command: roscreate-pkg beginner_tutorials std_msgs rospy roscpp 'beginner_tutorials' is created and than I got this: ERROR: ...
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rospack depends geometry_msgs vs rosmsg packages Header

Hi, I am using ROS Fuerte on Ubuntu 12.04 and I have some problem in understanding the consistency of the output of the following two commands: ...
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