#include <db.h>

int
DB_ENV->get_ext_file_threshold(DB_ENV *dbenv, u_int32_t *bytes);  

The DB_ENV->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_ENV->set_ext_file_threshold(). A value of 0 indicates that external files are not in use by default in this environment, unless DB->set_ext_file_threshold() is called to set an external file threshold for a specific database.

The DB_ENV->get_ext_file_threshold() method always returns 0 to indicate success.