编译ORB_SLAM3：error: ‘decay_t’ is not a member of ‘std’

:1. 安装Pangolin

# Get Pangolin
cd ~/your_fav_code_directory
git clone --recursive https://github.com/stevenlovegrove/Pangolin.git
cd Pangolin 

# Install dependencies (as described above, or your preferred method)
./scripts/install_prerequisites.sh recommended

# Configure and build
mkdir build && cd build
cmake ..
cmake --build .

# GIVEME THE PYTHON STUFF!!!! (Check the output to verify selected python version)
cmake --build . -t pypangolin_pip_install

# Run me some tests! (Requires Catch2 which must be manually installed on Ubuntu.)
ctest

sudo make install

2. OpenCV 切换

我的环境安装了OpenCV3 与 OpenCV4，默认设置是OpenCv3.

修改CmakeLists：

find_package(OpenCV 4.4)
改成
find_package(OpenCV 4 REQUIRED)

3. Eigen3

可直接编译也可直接apt安装

4. 编译ORB SLAM3

git clone https://github.com/UZ-SLAMLab/ORB_SLAM3.git ORB_SLAM3

cd ORB_SLAM3
chmod +x build.sh
./build.sh

出现错误：error: ‘decay_t’ is not a member of ‘std’

修改编译c++版本

CHECK_CXX_COMPILER_FLAG("-std=c++11" COMPILER_SUPPORTS_CXX11)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

修改成c++14版本

CHECK_CXX_COMPILER_FLAG("-std=c++14" COMPILER_SUPPORTS_CXX11)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14")

如果在vm虚拟机上出现：fatal error:Killed signal terminated program cc1plus

调大虚拟机内存，调低make -j x