Setting The Subtype Of An SQL Function
\ void sqlite3_result_subtype(sqlite3_context*,unsigned int);\
The sqlite3_result_subtype(C,T) function causes the subtype of the result from the application-defined SQL function with sqlite3_context C to be the value T. Only the lower 8 bits of the subtype T are preserved in current versions of SQLite; higher order bits are discarded. The number of subtype bytes preserved by SQLite might increase in future releases of SQLite.
Every application-defined SQL function that invokes this interface should include the SQLITE_RESULT_SUBTYPE property in its text encoding argument when the SQL function is registered. If the SQLITE_RESULT_SUBTYPE property is omitted from the function that invokes sqlite3_result_subtype(), then in some cases the sqlite3_result_subtype() might fail to set the result subtype.
If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any SQL function that invokes the sqlite3_result_subtype() interface and that does not have the SQLITE_RESULT_SUBTYPE property will raise an error. Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1 by default.