Here is a list of all related documentation pages:

SECURITY
C-SDK Resource Information
Configure TLS Protocol Version and Ciphers
Azure IoT Device Client C SDK
Prepare your development environment
Cross Compiling the SDK in a Docker Container
Getting start with IoTHub C SDK on iOS
SDK CMake integration with your application
IoT Hub C SDK Options
master to main branch rename instructions
Multiplexing limitations and alternatives
Running the C SDK on Constrained Devices
Run End to End Tests
CocoaPods for Microsoft Azure IoT
Using vcpkg for the Azure IoT C SDK to build device applications
Threading model and optimizing for resource constrained devices
Updating submodules for the C SDK
Using OpenSSL on IoT SDK on Windows
Deprecated List