The C SDK provides a framework for building EdgeX device services in C.

• A Linux build host
• A version of GCC supporting C11.
• CMake version 3 or greater and make.
• Development libraries and headers for:
  • curl (version 7.56 or later)
  • microhttpd (version 0.9)
  • libyaml (version 0.1.6 or later)
  • libcbor (version 0.5)
  • paho (version 1.3.x)
  • libuuid (from util-linux v2.x)
  • hiredis (version 0.14)
  • IOTech's C utilities package (version 1.5)

On Debian 11 "Bullseye" the requred system libraries can be installed by

apt-get install libcurl4-openssl-dev libmicrohttpd-dev libyaml-dev libcbor-dev libpaho-mqtt-dev libhiredis-dev

To install the C utilities see README.IOT.md

At the toplevel C SDK directory, run

make

This retrieves dependencies and uses CMake to build the SDK. Subsequent rebuilds may be performed by moving to the build/release or build/debug directories and running make.

A .tar.gz file containing the SDK headers and library is created in the build/{debug, release} directories. When building on some distributions a .deb or .rpm file is also created, as appropriate.

The main include file devsdk/devsdk.h contains the functions provided by the SDK and defines the callbacks which a device service implementor needs to create. Documentation is provided within that file in doxygen format. An outline device service and various examples are provided in src/c/examples to illustrate usage.

To build the SDK in a docker image, run the following command:

make docker

This will generate the sdk files in a results directory at the root of this project.

Alternatively, you can build a docker image which can be used to build device services in, with the following command:

docker build -t edgex-csdk-base:2.1.0 -f scripts/Dockerfile.alpine-base .

You can then write a Dockerfile for your service that begins FROM edgex-csdk-base:2.1.0

Please refer to the EdgeX Foundry versioning policy for information on how EdgeX services are released and how EdgeX services are compatible with one another. Specifically, device services (and the associated SDK), application services (and the associated app functions SDK), and client tools (like the EdgeX CLI and UI) can have independent minor releases, but these services must be compatible with the latest major release of EdgeX.

Please refer to the EdgeX Foundry LTS policy for information on support of EdgeX releases. The EdgeX community does not offer support on any non-LTS release outside of the latest release.