The SDK is provided as-is by Canon to select developers (though anyone can download it). The official documentation assumes you are an experienced C/C++ developer comfortable with handles, pointers, and asynchronous events.

The EDSDK is a set of libraries and APIs that enable developers to access and control Canon EOS cameras. The SDK provides a comprehensive set of tools and resources for creating applications that can capture, control, and manage images from Canon cameras.

Trigger the shutter, toggle autofocus/manual focus, and manage video recording from a computer.

This is the core of the SDK. Developers can programmatically adjust virtually every setting available on the camera body: