Raspberry Pico C/C++ SDK - Set up C++23 capable toolchain

2 Aug 2024

The Pico C/C++ SDK 1.5, when installed with the windows installer, comes with GCC version 10.3.1. That version supports C++ up to C++2a. Any GCC with version > 10 supports C++23.
In this little post, I install GCC 13.3, build my project with it, and validate it with the SDK (and VSCode).

The easiest way to do this, is to install the ARM cross compiler for arm bare metal. If you accept all default settings, this toolchain will be auto-detected by VSCode on next start.

Download the installer from https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads. Look for the Windows (mingw-w64-i686) hosted cross toolchains AArch32 bare-metal target (arm-none-eabi) section. Execute the installer. When prompted, leave the check for "configure registry settings" on. If you know what you are doing, you can alter other settings. When unsure, accept all defaults.

Restart VSCode. When defining the build, you can now select the new 13.3 toolchain:

To enable the C++23 standard, maintain the relevant setting in your project CMake file:

project(pico_gps_teseo C CXX ASM)

set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 23)

pico_sdk_init()

I tested it for this project, that needs C++23: C++ parser library for NMEA GPS data - pt. 1: ideas, concepts, early design

As extra test, I also built all the examples of the SDK 1.5 Pico examples:

[build] [6377/6377 100% :: 206.086] Linking CXX executable watchdog\hello_watchdog\hello_watchdog.elf
[driver] Build completed: 00:03:26.155
[build] Build finished with exit code 0

The install is non-intrusive, except if you let it change the path. You can either uncheck that option if you don't want that. Or remove the gcc13.3.1 bin directory from your path later on, via your Windows settings.
In any case, you will still be able to select and use the original GCC 10.3.1 that comes with the Pico SDK.

Jan, I don't use VSCode!

Other IDEs will have similar methods to select the new toolchain.

If you use command line, you can select the new toolchain via the parameters (works for Linux and Windows, as long as you use forward slashes for the path separator):

mkdir build
cd build
cmake .. -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_C_COMPILER:FILEPATH=/opt/gcc-arm-none-eabi/bin/arm...

Also works if you're building on a GitHub hosted server via GitHub Actions (see 1st comment below):

Top Comments

Jan Cumps 3 months ago +1

The github repository that I use for the project I used above, validates if your (my ) code builds, when a pull request is made for the develop or main branch: GitHub: automate Raspberry Pico project build…

Jan Cumps 3 months ago

The github repository that I use for the project I used above, validates if your (my ) code builds, when a pull request is made for the develop or main branch: GitHub: automate Raspberry Pico project build verification with GitHub Actions

This verification runs on GitHub hosted virtual machines.

The GitHub action installed the default version of the GCC cross-compile toolchain for the Linux server that the action happens to run on:

      - name: Install dependencies
        run: |
          sudo apt-get install cmake

           sudo apt install gcc-arm-none-eabi
           /usr/bin/arm-none-eabi-gcc --version

At this moment, that's version 10.3. Not high enough to compile C++23 constructs.

I adapted the build file to download and install the most recent version of the toolchain:

      - name: Install dependencies
        run: |
          sudo apt-get install cmake
          curl -Lo gcc-arm-none-eabi.tar.xz "https://developer.arm.com/-/media/Files/downloads/gnu/13.3.rel1/binrel/arm-gnu-toolchain-13.3.rel1-x86_64-arm-none-eabi.tar.xz"
          sudo mkdir /opt/gcc-arm-none-eabi
          sudo tar xf gcc-arm-none-eabi.tar.xz --strip-components=1 -C /opt/gcc-arm-none-eabi
          echo 'export PATH=$PATH:/opt/gcc-arm-none-eabi/bin' | sudo tee -a /etc/profile.d/gcc-arm-none-eabi.sh
          export PATH=$PATH:/opt/gcc-arm-none-eabi/bin
          export PICO_TOOLCHAIN_PATH=/opt/gcc-arm-none-eabi/bin
          source /etc/profile
          arm-none-eabi-c++ --version

I then adapted the build section to find the toolchain:

- name: Build Project
  working-directory: ${{github.workspace}}/pico_gps_teseo
  shell: bash
  run: |
    mkdir build
    cd build
    cmake .. -G "Unix Makefiles" -DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE -DCMAKE_C_COMPILER:FILEPATH=/opt/gcc-arm-none-eabi/bin/arm...

It works:

PICO compiler is pico_arm_gcc

-- The C compiler identification is GNU 13.3.1

-- The CXX compiler identification is GNU 13.3.1

[ 50%] Linking CXX executable pico_gps_teseo_reply_response.elf
[ 50%] Built target pico_gps_teseo_reply_response
...
[ 92%] Linking CXX executable pico_gps_teseo_nmea_parse.elf
[ 92%] Built target pico_gps_teseo_nmea_parse