LocalDBStartTracing Function
Applies to: 
SQL Server
Enables tracing of API calls for all the SQL Server Express LocalDB instances owned by the current Windows user.
Header file: msoledbsql.h
Syntax
HRESULT LocalDBStartTracing();
Returns
S_OK
The function succeeded.
LOCALDB_ERROR_XEVENT_FAILED
Failed to start XEvent engine within the LocalDB Instance API.
LOCALDB_ERROR_INTERNAL_ERROR
An unexpected error occurred. See the event log for details.
Remarks
For a code sample that uses LocalDB API, see SQL Server Express LocalDB Reference.