--- /dev/null
+`TRACE_EMERG`::
+ System is unusable.
+
+`TRACE_ALERT`::
+ Action must be taken immediately.
+
+`TRACE_CRIT`::
+ Critical conditions.
+
+`TRACE_ERR`::
+ Error conditions.
+
+`TRACE_WARNING`::
+ Warning conditions.
+
+`TRACE_NOTICE`::
+ Normal, but significant, condition.
+
+`TRACE_INFO`::
+ Informational message.
+
+`TRACE_DEBUG_SYSTEM`::
+ Debug information with system-level scope (set of programs).
+
+`TRACE_DEBUG_PROGRAM`::
+ Debug information with program-level scope (set of processes).
+
+`TRACE_DEBUG_PROCESS`::
+ Debug information with process-level scope (set of modules).
+
+`TRACE_DEBUG_MODULE`::
+ Debug information with module (executable/library) scope (set of units).
+
+`TRACE_DEBUG_UNIT`::
+ Debug information with compilation unit scope (set of functions).
+
+`TRACE_DEBUG_FUNCTION`::
+ Debug information with function-level scope.
+
+`TRACE_DEBUG_LINE`::
+ Debug information with line-level scope (default log level).
+
+`TRACE_DEBUG`::
+ Debug-level message.