#include <db.h> int DB->get_ext_file_threshold(DB *db, u_int32_t *bytes);
         The DB->get_ext_file_threshold() method
         returns the threshold value, in bytes, beyond which data items are
         stored as external files. This value can be set using
         DB->set_ext_file_threshold(). A value of 0 indicates
         that external files are not in use for this database.
    
         The DB->get_ext_file_threshold() method
         always returns 0 to indicate success.