1 files changed, 6 insertions, 2 deletions
diff --git a/gc.c b/gc.c
index ebd36cc3e8..38476df831 100644
--- a/gc.c
+++ b/gc.c
@@ -3117,8 +3117,12 @@ set_zero(st_data_t key, st_data_t val, st_data_t arg)
  *	}
  *
  *  The contents of the returned hash are implementation specific.
- *  It may be changed in future. The +:TOTAL+ key contains the count
- *  of all currently allocated and previously freed objects.
+ *  It may be changed in future.
+ *
+ *  The keys starting with +:T_+ means live objects.
+ *  For example, +:T_ARRAY+ is the number of arrays.
+ *  +:FREE+ means object slots which is not used now.
+ *  +:TOTAL+ means sum of above.
  *
  *  If the optional argument +result_hash+ is given,
  *  it is overwritten and returned. This is intended to avoid probe effect.