About run build_ros.sh

[shaw2001]

ubuntu 20.04
VirtualBox
had added
export ROS_PACKAGC_PATH

'Building ROS nodes
CMake Warning (dev) in CMakeLists.txt:
No project() command is present. The top-level CMakeLists.txt file must
contain a literal, direct call to the project() command. Add a line of
code such as

project(ProjectName)

near the top of the file, but after cmake_minimum_required().

CMake is pretending there is a "project(Project)" command on the first
line.
This warning is for project developers. Use -Wno-dev to suppress it.

-- The C compiler identification is GNU 9.4.0
-- The CXX compiler identification is GNU 9.4.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: /usr/bin/cc - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:7 (cmake_policy):
The OLD behavior for policy CMP0011 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
Call Stack (most recent call first):
CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:16 (cmake_policy):
The OLD behavior for policy CMP0002 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
Call Stack (most recent call first):
CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:18 (cmake_policy):
The OLD behavior for policy CMP0003 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
Call Stack (most recent call first):
CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:20 (cmake_policy):
The OLD behavior for policy CMP0005 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
Call Stack (most recent call first):
CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:23 (cmake_policy):
The OLD behavior for policy CMP0011 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.
Call Stack (most recent call first):
CMakeLists.txt:2 (include)

-- Found PythonInterp: /usr/bin/python (found version "2.7.18")
[rosbuild] Building package ORB_SLAM3
[rosbuild] Error from syntax check of ORB_SLAM3/manifest.xml
Traceback (most recent call last):
File "", line 1, in
File "/opt/ros/noetic/lib/python3/dist-packages/roslib/init.py", line 50, in
from roslib.launcher import load_manifest # noqa: F401
File "/opt/ros/noetic/lib/python3/dist-packages/roslib/launcher.py", line 42, in
import rospkg
ImportError: No module named rospkg
CMake Error at /opt/ros/noetic/share/ros/core/rosbuild/private.cmake:77 (message):
[rosbuild] Syntax check of ORB_SLAM3/manifest.xml failed; aborting
Call Stack (most recent call first):
/opt/ros/noetic/share/ros/core/rosbuild/public.cmake:174 (_rosbuild_check_manifest)
CMakeLists.txt:5 (rosbuild_init)

-- Configuring incomplete, errors occurred!
See also "/home/shaw/ORB_SLAM3/Examples/ROS/ORB_SLAM3/build/CMakeFiles/CMakeOutput.log".
make: *** 没有指明目标并且找不到 makefile。 停止。'

[jiangshuili]

how to solve it

[nutupodebil]

download "python-is-python3" using this command:
sudo apt-get install python-is-python3