An application can use different methods on different connections and can switch back and forth between the two methods, but these techniques are not useful in typical applications.
When moving from the inline to the callback method, installing either type of message callback for a connection turns off inline error handling. Client-Library discards any saved messages.
When moving from the callback to the inline method, calling ct_diag to initialize inline message handling deinstalls a connection’s message callbacks. If this occurs, the connection’s first call to ct_diag retrieves a warning message.
