Hello, there. This the first time I ask for help on ANSWER ROS. THANK YOU. I have some problems with an open source github project. The address of the project is link text I encountered some errors when I implemented the command "catkin build depth_segmentation". It returns the feedbacks like this:

Profile: default Extending: [explicit] /opt/ros/melodic

Workspace: /home/timothy/catkin_ws

Build Space: [exists] /home/timothy/catkinws/build Devel Space: [exists] /home/timothy/catkinws/devel Install Space: [unused] /home/timothy/catkinws/install Log Space: [exists] /home/timothy/catkinws/logs Source Space: [exists] /home/timothy/catkin_ws/src

DESTDIR: [unused] None

Devel Space Layout: merged

Install Space Layout: None

Additional CMake Args: -DCMAKECXXSTANDARD=14 -DCMAKEBUILDTYPE=Release Additional Make Args: None Additional catkin Make Args: None Internal Make Job Server: True

Cache Job Environments: False

Whitelisted Packages: None

Blacklisted Packages: None

Workspace configuration appears valid.

[build] Found '14' packages in 0.0 seconds.
[build] Package table is up to date.
Starting >>> catkinsimple
Finished <<< catkinsimple [ 0.1 seconds ]
Starting >>> eigencatkin
Starting >>> gflagscatkin
Starting >>> opencv3catkin
Starting >>> pclcatkin
Finished <<< pclcatkin [ 0.2 seconds ]
Finished <<< eigencatkin [ 0.1 seconds ]
Finished <<< gflagscatkin [ 0.1 seconds ]
Starting >>> glogcatkin
Finished <<< glog_catkin [ 0.1 seconds ]

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Errors << opencv3catkin:make /home/timothy/catkinws/logs/opencv3catkin/build.make.019.log
make[3]: warning: -jN forced in submake: disabling jobserver mode. In file included from /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/src/precomp.hpp:46:0, from /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/src/ellipticKeyPoint.cpp:5: /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:88:18: error: variable ‘cv::cuda::CVEXPORTS cv::cuda::SURFCUDA’ has initializer but incomplete type class CVEXPORTS SURFCUDA ^~~~~~~~~ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:90:1: error: expected primary-expression before ‘public’ public: ^~~~~~ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:90:1: error: expected ‘}’ before ‘public’ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:90:1: error: expected ‘,’ or ‘;’ before ‘public’ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:104:16: error: expected constructor, destructor, or type conversion before ‘;’ token SURFCUDA(); ^ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:107:104: error: ISO C++ forbids declaration of ‘SURFCUDA’ with no type [-fpermissive] int _nOctaveLayers=2, bool _extended=false, float _keypointsRatio=0.01f, bool _upright = false); ^ /home/timothy/catkinws/build/opencv3catkin/opencv3contribsrc/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:106:5: error: ‘explicit’ outside class declaration explicit SURFCUDA(double hessianThreshold, int _nOctaves=4, ^~~~~~~~ /home/timothy/catkinws/build/opencv3catkin/opencv3contrib_src/modules/xfeatures2d/include/opencv2/xfeatures2d/cuda.hpp:110:26: error: non-member function ‘int cv::cuda::descriptorSize()’ cannot have cv-qualifier int descriptorSize() const;