C/C++ applications only. Other components, such as UltraLite.NET, do not require a separate parameter to handle user data and so have no User Data parameter.

The syntax varies depending on the API you use.

When implementing the synchronization observer callback function or event handler, you can make application-specific information available by providing information using the User Data parameter.

• Observer synchronization parameter
• UltraLite C/C++: ul_sync_info structure