These links should help you get started learning about programming with YumaPro APIs.
The API Quickstart has an overview of most the server callback interfaces.
A callback function has to be registered at init time and unregistered at cleanup time.
These details are specified in the API Quickstart Guide:
There are many callbacks that are available during an edit transaction on the server. This includes server boot-time
transferring all NV-stored YANG configuration to the SIL and SIL-SA callbacks. It also includes all run-time edits done
by a client protocol or a DB-API subsystem edit.
The yp-system library allows many system-level APIs to be added to the server at boot-time. These APIs are not related to specific YANG objects.
The yp-client library can be used to create simple C++ client applications using yangcli-pro session features.
NETCONF over SSH and NETCONF over TLS sessions can be managed, and yangcli-pro functionality accessed from a custom C++ program.
YumaWorks documentation is freely available on our website: https://www.yumaworks.com/downloads/.