include <sys/queue.h> in header files that require it, not in .c files.
encode and decode time of a query even though it is not properly set yet.
hold a score of a searching result even though it is not computed yet.
cosmetic change.
hold a time of a retrieved data even though it is not used yet.
include a locator type in a query.
set errno on a conversion failure of a keyword.
add a function to convert a formula type to its name.
return NULL when there is no matching database name.
add useful functions to handle packets.
implement a trivial file based database for KCN.
do not duplicatedly output the almost same logging message.
accept NULL when destroying packet data.
implement functions to add a record into a database table.
support multiple contiguous message exchanges.
clean up code.