The GetOldestEventLogRecord function retrieves the absolute record number of the oldest record in the specified event log.
BOOL GetOldestEventLogRecord(
| 
 HANDLE hEventLog,  | 
 // handle to event log  | 
| 
 PDWORD OldestRecord  | 
 // buffer for number of oldest record  | 
| 
 );  | 
If the function succeeds, the return value is nonzero.
If the function fails, the return value is zero. To get extended error information, call GetLastError.
GetNumberOfEventLogRecords, OpenBackupEventLog, OpenEventLog