RB_KEY_NOT_FOUND "key not found in rbtree"
BAD_ROW_NUM "invalid row number"
INDEX_CORRUPTION "index corruption detected"
-INVALID_OBJECT "reference to invalid object"
LSEEK "lseek error"
BUSY "table is busy"
SHORT_TABLE "table too short"
EMPTY "file empty"
MMAP "mmap error"
LOOP "loop terminated"
+NOMEM "cannot allocate memory"
+NOTDIR "not a directory"
+STAT "stat error"
+UNLINK "failed to unlink file"