Nanopb - Protocol Buffers for Embedded Systems

Nanopb is a small code-size Protocol Buffers implementation in ansi C. It isespecially suitable for use in microcontrollers, but fits any memoryrestricted system.

• Homepage: https://jpa.kapsi.fi/nanopb/
• Documentation: https://jpa.kapsi.fi/nanopb/docs/
• Downloads: https://jpa.kapsi.fi/nanopb/download/
• Forum: https://groups.google.com/forum/#!forum/nanopb
• Nightly builds: https://jpa.kapsi.fi/jenkins/job/nanopb/

Using the nanopb library

To use the nanopb library, you need to do two things:

1. Compile your .proto files for nanopb, using protoc.
2. Include pb_encode.c, pb_decode.c and pb_common.c in your project.

The easiest way to get started is to study the project in "examples/simple".It contains a Makefile, which should work directly under most Linux systems.However, for any other kind of build system, see the manual steps inREADME.txt in that folder.

Generating the headers

Protocol Buffers messages are defined in a .proto file, which follows a standardformat that is compatible with all Protocol Buffers libraries. To use it with nanopb,you need to generate .pb.c and .pb.h files from it:

python generator/nanopb_generator.py myprotocol.proto  # For source checkout
generator-bin/nanopb_generator myprotocol.proto        # For binary package

(Note: For instructions for nanopb-0.3.9.x and older, see the documentationof that particular version here)

The binary packages for Windows, Linux and Mac OS X should contain all necessarydependencies, including Python, python-protobuf library and protoc. If you areusing a git checkout or a plain source distribution, you will need to installPython separately. Once you have Python, you can install the other dependencieswith pip install protobuf grpcio-tools.

You can further customize the header generation by creating an .options file.See documentation for details.

Running the tests

If you want to perform further development of the nanopb core, or to verifyits functionality using your compiler and platform, you'll want to run thetest suite. The build rules for the test suite are implemented using Scons,so you need to have that installed (ex: sudo apt install scons or pip install scons).To run the tests:

cd tests
scons

This will show the progress of various test cases. If the output does notend in an error, the test cases were successful.

Note: Mac OS X by default aliases 'clang' as 'gcc', while not actuallysupporting the same command line options as gcc does. To run tests onMac OS X, use: scons CC=clang CXX=clang. Same way can be used to runtests with different compilers on any platform.

For embedded platforms, there is currently support for running the testson STM32 discovery board and simavrAVR simulator. Use scons PLATFORM=STM32 and scons PLATFORM=AVR to runthese tests.

Build systems and integration

Nanopb C code itself is designed to be portable and easy to buildon any platform. Often the bigger hurdle is running the generator whichtakes in the .proto files and outputs .pb.c definitions.

There exist build rules for several systems:

• Makefiles: extra/nanopb.mk, see examples/simple
• CMake: extra/FindNanopb.cmake, see examples/cmake
• SCons: tests/site_scons (generator only)
• Bazel: BUILD in source root
• Conan: conanfile.py in source root
• PlatformIO: https://platformio.org/lib/show/431/Nanopb
• PyPI/pip: https://pypi.org/project/nanopb/

And also integration to platform interfaces:

• Arduino: http://platformio.org/lib/show/1385/nanopb-arduino

Building nanopb - Using vcpkg

You can download and install nanopb using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install nanopb

The nanopb port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.