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can't call member without object?

asked 2018-03-12 08:40:39 -0600

dinesh gravatar image

i'm using ros kinetic.

In file included from /home/robot/youbot_catkin_ws/src/youbot-controller/src/localisation-component.cpp:1:0:
/home/robot/youbot_catkin_ws/src/youbot-controller/src/localisation-component.hpp: In member function ‘virtual void Localisation::updateHook()’:
/home/robot/youbot_catkin_ws/src/youbot-controller/src/localisation-component.hpp:37:80: error: cannot call member function ‘void KDL::Rotation::GetQuaternion(double&, double&, double&, double&) const’ without object
             KDL::Rotation rot = KDL::Rotation::GetQuaternion(qu.x, qu.y, qu.z, qu.w);
                                                                                    ^
    youbot-controller/CMakeFiles/localisation-component.dir/build.make:62: recipe for target 'youbot-controller/CMakeFiles

/localisation-component.dir/src/localisation-component.cpp.o' failed
    make[2]: *** [youbot-controller/CMakeFiles/localisation-component.dir/src/localisation-component.cpp.o] Error 1
    CMakeFiles/Makefile2:407: recipe for target 'youbot-controller/CMakeFiles/localisation-component.dir/all' failed
    make[1]: *** [youbot-controller/CMakeFiles/localisation-component.dir/all] Error 2
    Makefile:138: recipe for target 'all' failed
    make: *** [all] Error 2
    Invoking "make -j4 -l4" failed

here is d source file:

#ifndef OROCOS_LOCALISATION_COMPONENT_HPP
#define OROCOS_LOCALISATION_COMPONENT_HPP

    #include <rtt/RTT.hpp>
    #include <iostream>
    #include <geometry_msgs/Pose2D.h>
    #include <geometry_msgs/TransformStamped.h>
    #include <kdl/frames.hpp>

    class Localisation
        : public RTT::TaskContext
    {
        geometry_msgs::TransformStamped tfs;
        RTT::OutputPort<geometry_msgs::Pose2D> outpose;
     public:
        Localisation(std::string const& name)
            : TaskContext(name, PreOperational)
        {
        addPort("pose", outpose).doc("Contains latest Youbot Pose.");
    }

    bool configureHook() {
        /** Check in here that we can call rtt_tf */
        return false;
    }

    void updateHook() {
        try {
            /* tfs = ...call rtt_tf and query the transform /odom to /base_footprint ... ; */
        } catch (...) {
            return;
        }
        geometry_msgs::Pose2D pose;
        pose.x = tfs.transform.translation.x;
        pose.y = tfs.transform.translation.y;
        geometry_msgs::Quaternion qu = tfs.transform.rotation;
        KDL::Rotation rot = KDL::Rotation::GetQuaternion(qu.x, qu.y, qu.z, qu.w);
        //KDL::Vector v;
        //pose.theta = rot.GetRotAngle(v);
        //outpose.write(pose); 
    }
};

#endif
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answered 2018-03-12 09:15:22 -0600

gvdhoorn gravatar image

updated 2018-03-13 01:36:48 -0600

This is a C++ issue and not a ROS one: KDL::Rotation::GetQuaternion(..) is not a static method, but a regular one. From the documentation:

Get the quaternion of this matrix

You'll need to first create an instance of KDL::Rotation ('this matrix') and then invoke its GetQuaternion(..).

Note also: x, y, z and w are output arguments.


Edit:

KDL::Rotation rot;
rot.GetQuaternion(qu.x, qu.y, qu.z, qu.w);

stil i'm getting same error.

error is:

undefined reference to `KDL::Rotation::GetQuaternion(double&, double&, double&, double&) const'

So which is it? The same error, or this last one?

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Comments

KDL::Rotation rot; rot.GetQuaternion(qu.x, qu.y, qu.z, qu.w); stil i'm getting same error.

dinesh gravatar imagedinesh ( 2018-03-13 00:10:36 -0600 )edit

error is: undefined reference to `KDL::Rotation::GetQuaternion(double&, double&, double&, double&) const'

dinesh gravatar imagedinesh ( 2018-03-13 00:11:32 -0600 )edit

the full error is: CMakeFiles/localisation-component.dir/src/localisation-component.cpp.o: In function Localisation::updateHook()': localisation-component.cpp:(.text._ZN12Localisation10updateHookEv[_ZN12Localisation10updateHookEv]+0xee): undefined reference toKDL::Rotation::Quaternion(double, dou

dinesh gravatar imagedinesh ( 2018-03-13 06:15:33 -0600 )edit

Please add this sort of updates to your original question. Use the edit button/link for that.

gvdhoorn gravatar imagegvdhoorn ( 2018-03-13 06:18:10 -0600 )edit

The linker error would seem to be similar to what you ask about in #q285133.

If you've solved the "cannot call member function" error, then is this question answered?

gvdhoorn gravatar imagegvdhoorn ( 2018-03-14 04:30:44 -0600 )edit

well this error is done by using object of class kdl::rotation but when i do it, the previous error i.e undefined reference to kdl::rotation::quaternion .. is comming. so now i'm reinstalling ros desktop full this time. previously i was using ros kinetic not full version, and gazebo 9.

dinesh gravatar imagedinesh ( 2018-03-14 04:39:23 -0600 )edit

If your question about "cannot call member function" was answered, then please tick the checkmark to the left of this answer.

gvdhoorn gravatar imagegvdhoorn ( 2018-03-14 04:49:05 -0600 )edit

so now i'm reinstalling ros desktop full this time. previously i was using ros kinetic not full version, and gazebo 9.

I would be surprised if that will solve anything, but you never know.

gvdhoorn gravatar imagegvdhoorn ( 2018-03-14 04:49:27 -0600 )edit

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Asked: 2018-03-12 08:40:39 -0600

Seen: 184 times

Last updated: Mar 13 '18