x—one of t, nil, or :default.
room prints, to standard output,
information about the state of internal storage and its management.
This might include descriptions of the amount of memory in use and
the degree of memory compaction, possibly broken down by internal data type if that
is appropriate. The nature and format of the printed information is
implementation-dependent.
The intent is to provide information that a programmer
might use to tune a program for a particular implementation.
(room nil) prints out a minimal amount of information.
(room t) prints out a maximal amount of information.
(room) or (room :default) prints out an intermediate amount
of information that is likely to be useful.
Output to standard output.
*standard-output*.