| Value | Meaning | 
|---|---|
| trace | Developer information for locating events when no useful stack traces are available  | 
| debugV | Developer information useful for algorithm debugging - for verbose output  | 
| debug_ | Developer information useful for algorithm debugging  | 
| diagnostic | Extended user information (e.g. for more detailed error information)  | 
| info | Informational message for normal user education  | 
| warn | Unexpected condition that could indicate an error but has no direct consequences  | 
| error | Normal error that is handled gracefully  | 
| critical | Error that severely influences the execution of the application  | 
| fatal | Error that forces the application to terminate  | 
| none | Special value used to indicate no logging when set as the minimum log level  | 
| verbose1diagnostic | Alias for diagnostic messages  | 
| verbose2debug_ | Alias for debug messages  | 
| verbose3debugV | Alias for verbose debug messages  | 
| verbose4trace | Alias for trace messages  | 
Specifies the log level for a particular log message.