Special property of default_debug logging channel

[Chris Thompson]

To quote from the ARM:

| The default_debug channel has the special property that it only
| produces output when the server's debug level is nonzero. 

Is it possible to define one's own logging channels that behave similarly?
Just specifying "severity dynamic" is not enough: one gets info level
logging after "rndc notrace" rather than no logging at all.

The problem is that one may want something with slightly different
properties than default_debug, e.g. print-category or print-severity
settings, versions, size etc., but still want to keep this "special
property".

-- 
Chris Thompson
Email: cet1 at cam.ac.uk