CTR Mode AES Block Chain Cipher

C++17 set up RPi(arm7)* to use CLang 8 and CMAKE files

*not RPi Zero(arm6) - see Pi Zero GCC 9 and CMAKE

1. Setup CLang 8

Download the official binary of CLang 8 for Raspberry Pi

cd ~
wget http://releases.llvm.org/8.0.0/clang+llvm-8.0.0-armv7a-linux-gnueabihf.tar.xz
#Raspbery Pi Zero is ARMv6 so will *not* work
#Zero uses the originalthanks to: 

Extract the archive and move the extracted compilers to /usr/local

tar -xf clang+llvm-8.0.0-armv7a-linux-gnueabihf.tar.xz
rm clang+llvm-8.0.0-armv7a-linux-gnueabihf.tar.xz
mv clang+llvm-8.0.0-armv7a-linux-gnueabihf clang_8.0.0
sudo mv clang_8.0.0 /usr/local

Add CLang to system search paths

echo 'export PATH=/usr/local/clang_8.0.0/bin:$PATH' >> .bashrc
echo 'export LD_LIBRARY_PATH=/usr/local/clang_8.0.0/lib:$LD_LIBRARY_PATH' >> .bashrc
source .bashrc
clang++ --version

Add CLang as a system option install as a new alternative:

sudo update-alternatives --install /usr/bin/cc cc /usr/local/clang_8.0.0/bin/clang 10
sudo update-alternatives --install /usr/bin/c++ c++ /usr/local/clang_8.0.0/bin/clang++ 10

Configure CLang for C and C++

sudo update-alternatives --config cc
sudo update-alternatives --config c++

  Selection    Path            Priority   Status
------------------------------------------------------------
* 0            /usr/bin/gcc     20        auto mode
  1            /usr/bin/clang   10        manual mode
  2            /usr/bin/gcc     20        manual mode
Press enter to keep the current choice[*], or type selection number:

Removal

sudo rm -rf /usr/local/clang_8.0.0

2. Setup CMAKE v3.14

Download CMAKE v 3.14 and extract it

wget https://cmake.org/files/v3.14/cmake-3.14.5.tar.gz
tar -xvzf cmake-3.14.5.tar.gz

Compile and install cmake

cd cmake-3.14.5/
sudo ./bootstrap
sudo make
sudo make install

Remove old CMAKE data

sudo apt-get remove cmake cmake-data

Direct OS to new CMAKE, reload bashrc and check version

export CMAKE_ROOT=/usr/share/cmake-3.14
. ~/.bashrc 
cmake --version

cmake version 3.14.5

CMake suite maintained and supported by Kitware (kitware.com/cmake).

3. Using CMAKE

Example CMakeList.txt optimize for memory footprint

cmake_minimum_required(VERSION 3.14)
project(ctr)

set(CMAKE_CXX_STANDARD 17)

if(NOT CMAKE_BUILD_TYPE)
    set(CMAKE_BUILD_TYPE Release)
endif()

set(CMAKE_CXX_FLAGS "-Wall")
set(CMAKE_CXX_FLAGS_DEBUG "--debug -Wextra")
set(CMAKE_CXX_FLAGS_RELEASE "-Os") #optimize for memory footprint

add_executable(ctr
        main.cpp)

Using CMAKE inside project directory containing CMakeLists.txt

mkdir build
cd build
cmake ..
make

thanks to:

• solarian programmer
• nick cullen